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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
35 #include "hard-reg-set.h"
36 #include "insn-config.h"
39 #include "langhooks.h"
41 static rtx break_out_memory_refs (rtx);
42 static void emit_stack_probe (rtx);
45 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
48 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode)
50 int width = GET_MODE_BITSIZE (mode);
52 /* You want to truncate to a _what_? */
53 if (! SCALAR_INT_MODE_P (mode))
56 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
58 return c & 1 ? STORE_FLAG_VALUE : 0;
60 /* Sign-extend for the requested mode. */
62 if (width < HOST_BITS_PER_WIDE_INT)
64 HOST_WIDE_INT sign = 1;
74 /* Return an rtx for the sum of X and the integer C.
76 This function should be used via the `plus_constant' macro. */
79 plus_constant_wide (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 (GET_CODE (XEXP (x, 1)) == CONST_INT)
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 (GET_CODE (XEXP (x, 1)) == CONST_INT
215 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
217 && GET_CODE (tem) == CONST_INT)
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 && GET_CODE (tem) == CONST_INT)
232 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
238 /* Return an rtx for the size in bytes of the value of EXP. */
243 tree size = (*lang_hooks.expr_size) (exp);
245 if (CONTAINS_PLACEHOLDER_P (size))
246 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
248 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
251 /* Return a wide integer for the size in bytes of the value of EXP, or -1
252 if the size can vary or is larger than an integer. */
255 int_expr_size (tree exp)
257 tree t = (*lang_hooks.expr_size) (exp);
260 || TREE_CODE (t) != INTEGER_CST
262 || TREE_INT_CST_HIGH (t) != 0
263 /* If the result would appear negative, it's too big to represent. */
264 || (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0)
267 return TREE_INT_CST_LOW (t);
270 /* Return a copy of X in which all memory references
271 and all constants that involve symbol refs
272 have been replaced with new temporary registers.
273 Also emit code to load the memory locations and constants
274 into those registers.
276 If X contains no such constants or memory references,
277 X itself (not a copy) is returned.
279 If a constant is found in the address that is not a legitimate constant
280 in an insn, it is left alone in the hope that it might be valid in the
283 X may contain no arithmetic except addition, subtraction and multiplication.
284 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
287 break_out_memory_refs (rtx x)
289 if (GET_CODE (x) == MEM
290 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
291 && GET_MODE (x) != VOIDmode))
292 x = force_reg (GET_MODE (x), x);
293 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
294 || GET_CODE (x) == MULT)
296 rtx op0 = break_out_memory_refs (XEXP (x, 0));
297 rtx op1 = break_out_memory_refs (XEXP (x, 1));
299 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
300 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
306 /* Given X, a memory address in ptr_mode, convert it to an address
307 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
308 the fact that pointers are not allowed to overflow by commuting arithmetic
309 operations over conversions so that address arithmetic insns can be
313 convert_memory_address (enum machine_mode to_mode ATTRIBUTE_UNUSED,
316 #ifndef POINTERS_EXTEND_UNSIGNED
318 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
319 enum machine_mode from_mode;
323 /* If X already has the right mode, just return it. */
324 if (GET_MODE (x) == to_mode)
327 from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
329 /* Here we handle some special cases. If none of them apply, fall through
330 to the default case. */
331 switch (GET_CODE (x))
335 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
337 else if (POINTERS_EXTEND_UNSIGNED < 0)
339 else if (POINTERS_EXTEND_UNSIGNED > 0)
343 temp = simplify_unary_operation (code, to_mode, x, from_mode);
349 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
350 && GET_MODE (SUBREG_REG (x)) == to_mode)
351 return SUBREG_REG (x);
355 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
356 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
361 temp = shallow_copy_rtx (x);
362 PUT_MODE (temp, to_mode);
367 return gen_rtx_CONST (to_mode,
368 convert_memory_address (to_mode, XEXP (x, 0)));
373 /* For addition we can safely permute the conversion and addition
374 operation if one operand is a constant and converting the constant
375 does not change it. We can always safely permute them if we are
376 making the address narrower. */
377 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
378 || (GET_CODE (x) == PLUS
379 && GET_CODE (XEXP (x, 1)) == CONST_INT
380 && XEXP (x, 1) == convert_memory_address (to_mode, XEXP (x, 1))))
381 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
382 convert_memory_address (to_mode, XEXP (x, 0)),
390 return convert_modes (to_mode, from_mode,
391 x, POINTERS_EXTEND_UNSIGNED);
392 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
395 /* Given a memory address or facsimile X, construct a new address,
396 currently equivalent, that is stable: future stores won't change it.
398 X must be composed of constants, register and memory references
399 combined with addition, subtraction and multiplication:
400 in other words, just what you can get from expand_expr if sum_ok is 1.
402 Works by making copies of all regs and memory locations used
403 by X and combining them the same way X does.
404 You could also stabilize the reference to this address
405 by copying the address to a register with copy_to_reg;
406 but then you wouldn't get indexed addressing in the reference. */
409 copy_all_regs (rtx x)
411 if (GET_CODE (x) == REG)
413 if (REGNO (x) != FRAME_POINTER_REGNUM
414 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
415 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
420 else if (GET_CODE (x) == MEM)
422 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
423 || GET_CODE (x) == MULT)
425 rtx op0 = copy_all_regs (XEXP (x, 0));
426 rtx op1 = copy_all_regs (XEXP (x, 1));
427 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
428 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
433 /* Return something equivalent to X but valid as a memory address
434 for something of mode MODE. When X is not itself valid, this
435 works by copying X or subexpressions of it into registers. */
438 memory_address (enum machine_mode mode, rtx x)
442 if (GET_CODE (x) == ADDRESSOF)
445 x = convert_memory_address (Pmode, x);
447 /* By passing constant addresses through registers
448 we get a chance to cse them. */
449 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
450 x = force_reg (Pmode, x);
452 /* Accept a QUEUED that refers to a REG
453 even though that isn't a valid address.
454 On attempting to put this in an insn we will call protect_from_queue
455 which will turn it into a REG, which is valid. */
456 else if (GET_CODE (x) == QUEUED
457 && GET_CODE (QUEUED_VAR (x)) == REG)
460 /* We get better cse by rejecting indirect addressing at this stage.
461 Let the combiner create indirect addresses where appropriate.
462 For now, generate the code so that the subexpressions useful to share
463 are visible. But not if cse won't be done! */
466 if (! cse_not_expected && GET_CODE (x) != REG)
467 x = break_out_memory_refs (x);
469 /* At this point, any valid address is accepted. */
470 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
472 /* If it was valid before but breaking out memory refs invalidated it,
473 use it the old way. */
474 if (memory_address_p (mode, oldx))
477 /* Perform machine-dependent transformations on X
478 in certain cases. This is not necessary since the code
479 below can handle all possible cases, but machine-dependent
480 transformations can make better code. */
481 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
483 /* PLUS and MULT can appear in special ways
484 as the result of attempts to make an address usable for indexing.
485 Usually they are dealt with by calling force_operand, below.
486 But a sum containing constant terms is special
487 if removing them makes the sum a valid address:
488 then we generate that address in a register
489 and index off of it. We do this because it often makes
490 shorter code, and because the addresses thus generated
491 in registers often become common subexpressions. */
492 if (GET_CODE (x) == PLUS)
494 rtx constant_term = const0_rtx;
495 rtx y = eliminate_constant_term (x, &constant_term);
496 if (constant_term == const0_rtx
497 || ! memory_address_p (mode, y))
498 x = force_operand (x, NULL_RTX);
501 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
502 if (! memory_address_p (mode, y))
503 x = force_operand (x, NULL_RTX);
509 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
510 x = force_operand (x, NULL_RTX);
512 /* If we have a register that's an invalid address,
513 it must be a hard reg of the wrong class. Copy it to a pseudo. */
514 else if (GET_CODE (x) == REG)
517 /* Last resort: copy the value to a register, since
518 the register is a valid address. */
520 x = force_reg (Pmode, x);
527 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
528 /* Don't copy an addr via a reg if it is one of our stack slots. */
529 && ! (GET_CODE (x) == PLUS
530 && (XEXP (x, 0) == virtual_stack_vars_rtx
531 || XEXP (x, 0) == virtual_incoming_args_rtx)))
533 if (general_operand (x, Pmode))
534 x = force_reg (Pmode, x);
536 x = force_operand (x, NULL_RTX);
542 /* If we didn't change the address, we are done. Otherwise, mark
543 a reg as a pointer if we have REG or REG + CONST_INT. */
546 else if (GET_CODE (x) == REG)
547 mark_reg_pointer (x, BITS_PER_UNIT);
548 else if (GET_CODE (x) == PLUS
549 && GET_CODE (XEXP (x, 0)) == REG
550 && GET_CODE (XEXP (x, 1)) == CONST_INT)
551 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
553 /* OLDX may have been the address on a temporary. Update the address
554 to indicate that X is now used. */
555 update_temp_slot_address (oldx, x);
560 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
563 memory_address_noforce (enum machine_mode mode, rtx x)
565 int ambient_force_addr = flag_force_addr;
569 val = memory_address (mode, x);
570 flag_force_addr = ambient_force_addr;
574 /* Convert a mem ref into one with a valid memory address.
575 Pass through anything else unchanged. */
578 validize_mem (rtx ref)
580 if (GET_CODE (ref) != MEM)
582 if (! (flag_force_addr && CONSTANT_ADDRESS_P (XEXP (ref, 0)))
583 && memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
586 /* Don't alter REF itself, since that is probably a stack slot. */
587 return replace_equiv_address (ref, XEXP (ref, 0));
590 /* Given REF, either a MEM or a REG, and T, either the type of X or
591 the expression corresponding to REF, set RTX_UNCHANGING_P if
595 maybe_set_unchanging (rtx ref, tree t)
597 /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
598 initialization is only executed once, or whose initializer always
599 has the same value. Currently we simplify this to PARM_DECLs in the
600 first case, and decls with TREE_CONSTANT initializers in the second. */
602 if ((TREE_READONLY (t) && DECL_P (t)
603 && (DECL_EXTERNAL (t)
604 || TREE_CODE (t) == PARM_DECL
605 || (DECL_INITIAL (t) && TREE_CONSTANT (DECL_INITIAL (t)))))
606 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
607 RTX_UNCHANGING_P (ref) = 1;
610 /* Return a modified copy of X with its memory address copied
611 into a temporary register to protect it from side effects.
612 If X is not a MEM, it is returned unchanged (and not copied).
613 Perhaps even if it is a MEM, if there is no need to change it. */
618 if (GET_CODE (x) != MEM
619 || ! rtx_unstable_p (XEXP (x, 0)))
623 replace_equiv_address (x, force_reg (Pmode, copy_all_regs (XEXP (x, 0))));
626 /* Copy the value or contents of X to a new temp reg and return that reg. */
631 rtx temp = gen_reg_rtx (GET_MODE (x));
633 /* If not an operand, must be an address with PLUS and MULT so
634 do the computation. */
635 if (! general_operand (x, VOIDmode))
636 x = force_operand (x, temp);
639 emit_move_insn (temp, x);
644 /* Like copy_to_reg but always give the new register mode Pmode
645 in case X is a constant. */
648 copy_addr_to_reg (rtx x)
650 return copy_to_mode_reg (Pmode, x);
653 /* Like copy_to_reg but always give the new register mode MODE
654 in case X is a constant. */
657 copy_to_mode_reg (enum machine_mode mode, rtx x)
659 rtx temp = gen_reg_rtx (mode);
661 /* If not an operand, must be an address with PLUS and MULT so
662 do the computation. */
663 if (! general_operand (x, VOIDmode))
664 x = force_operand (x, temp);
666 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
669 emit_move_insn (temp, x);
673 /* Load X into a register if it is not already one.
674 Use mode MODE for the register.
675 X should be valid for mode MODE, but it may be a constant which
676 is valid for all integer modes; that's why caller must specify MODE.
678 The caller must not alter the value in the register we return,
679 since we mark it as a "constant" register. */
682 force_reg (enum machine_mode mode, rtx x)
686 if (GET_CODE (x) == REG)
689 if (general_operand (x, mode))
691 temp = gen_reg_rtx (mode);
692 insn = emit_move_insn (temp, x);
696 temp = force_operand (x, NULL_RTX);
697 if (GET_CODE (temp) == REG)
698 insn = get_last_insn ();
701 rtx temp2 = gen_reg_rtx (mode);
702 insn = emit_move_insn (temp2, temp);
707 /* Let optimizers know that TEMP's value never changes
708 and that X can be substituted for it. Don't get confused
709 if INSN set something else (such as a SUBREG of TEMP). */
711 && (set = single_set (insn)) != 0
712 && SET_DEST (set) == temp
713 && ! rtx_equal_p (x, SET_SRC (set)))
714 set_unique_reg_note (insn, REG_EQUAL, x);
719 /* If X is a memory ref, copy its contents to a new temp reg and return
720 that reg. Otherwise, return X. */
723 force_not_mem (rtx x)
727 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
730 temp = gen_reg_rtx (GET_MODE (x));
731 emit_move_insn (temp, x);
735 /* Copy X to TARGET (if it's nonzero and a reg)
736 or to a new temp reg and return that reg.
737 MODE is the mode to use for X in case it is a constant. */
740 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode)
744 if (target && GET_CODE (target) == REG)
747 temp = gen_reg_rtx (mode);
749 emit_move_insn (temp, x);
753 /* Return the mode to use to store a scalar of TYPE and MODE.
754 PUNSIGNEDP points to the signedness of the type and may be adjusted
755 to show what signedness to use on extension operations.
757 FOR_CALL is nonzero if this call is promoting args for a call. */
760 promote_mode (tree type, enum machine_mode mode, int *punsignedp,
761 int for_call ATTRIBUTE_UNUSED)
763 enum tree_code code = TREE_CODE (type);
764 int unsignedp = *punsignedp;
766 #ifdef PROMOTE_FOR_CALL_ONLY
774 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
775 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
776 PROMOTE_MODE (mode, unsignedp, type);
780 #ifdef POINTERS_EXTEND_UNSIGNED
784 unsignedp = POINTERS_EXTEND_UNSIGNED;
792 *punsignedp = unsignedp;
796 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
797 This pops when ADJUST is positive. ADJUST need not be constant. */
800 adjust_stack (rtx adjust)
803 adjust = protect_from_queue (adjust, 0);
805 if (adjust == const0_rtx)
808 /* We expect all variable sized adjustments to be multiple of
809 PREFERRED_STACK_BOUNDARY. */
810 if (GET_CODE (adjust) == CONST_INT)
811 stack_pointer_delta -= INTVAL (adjust);
813 temp = expand_binop (Pmode,
814 #ifdef STACK_GROWS_DOWNWARD
819 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
822 if (temp != stack_pointer_rtx)
823 emit_move_insn (stack_pointer_rtx, temp);
826 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
827 This pushes when ADJUST is positive. ADJUST need not be constant. */
830 anti_adjust_stack (rtx adjust)
833 adjust = protect_from_queue (adjust, 0);
835 if (adjust == const0_rtx)
838 /* We expect all variable sized adjustments to be multiple of
839 PREFERRED_STACK_BOUNDARY. */
840 if (GET_CODE (adjust) == CONST_INT)
841 stack_pointer_delta += INTVAL (adjust);
843 temp = expand_binop (Pmode,
844 #ifdef STACK_GROWS_DOWNWARD
849 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
852 if (temp != stack_pointer_rtx)
853 emit_move_insn (stack_pointer_rtx, temp);
856 /* Round the size of a block to be pushed up to the boundary required
857 by this machine. SIZE is the desired size, which need not be constant. */
860 round_push (rtx size)
862 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
867 if (GET_CODE (size) == CONST_INT)
869 HOST_WIDE_INT new = (INTVAL (size) + align - 1) / align * align;
871 if (INTVAL (size) != new)
872 size = GEN_INT (new);
876 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
877 but we know it can't. So add ourselves and then do
879 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
880 NULL_RTX, 1, OPTAB_LIB_WIDEN);
881 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
883 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
889 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
890 to a previously-created save area. If no save area has been allocated,
891 this function will allocate one. If a save area is specified, it
892 must be of the proper mode.
894 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
895 are emitted at the current position. */
898 emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
901 /* The default is that we use a move insn and save in a Pmode object. */
902 rtx (*fcn) (rtx, rtx) = gen_move_insn;
903 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
905 /* See if this machine has anything special to do for this kind of save. */
908 #ifdef HAVE_save_stack_block
910 if (HAVE_save_stack_block)
911 fcn = gen_save_stack_block;
914 #ifdef HAVE_save_stack_function
916 if (HAVE_save_stack_function)
917 fcn = gen_save_stack_function;
920 #ifdef HAVE_save_stack_nonlocal
922 if (HAVE_save_stack_nonlocal)
923 fcn = gen_save_stack_nonlocal;
930 /* If there is no save area and we have to allocate one, do so. Otherwise
931 verify the save area is the proper mode. */
935 if (mode != VOIDmode)
937 if (save_level == SAVE_NONLOCAL)
938 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
940 *psave = sa = gen_reg_rtx (mode);
945 if (mode == VOIDmode || GET_MODE (sa) != mode)
954 /* We must validize inside the sequence, to ensure that any instructions
955 created by the validize call also get moved to the right place. */
957 sa = validize_mem (sa);
958 emit_insn (fcn (sa, stack_pointer_rtx));
961 emit_insn_after (seq, after);
966 sa = validize_mem (sa);
967 emit_insn (fcn (sa, stack_pointer_rtx));
971 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
972 area made by emit_stack_save. If it is zero, we have nothing to do.
974 Put any emitted insns after insn AFTER, if nonzero, otherwise at
978 emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
980 /* The default is that we use a move insn. */
981 rtx (*fcn) (rtx, rtx) = gen_move_insn;
983 /* See if this machine has anything special to do for this kind of save. */
986 #ifdef HAVE_restore_stack_block
988 if (HAVE_restore_stack_block)
989 fcn = gen_restore_stack_block;
992 #ifdef HAVE_restore_stack_function
994 if (HAVE_restore_stack_function)
995 fcn = gen_restore_stack_function;
998 #ifdef HAVE_restore_stack_nonlocal
1000 if (HAVE_restore_stack_nonlocal)
1001 fcn = gen_restore_stack_nonlocal;
1010 sa = validize_mem (sa);
1011 /* These clobbers prevent the scheduler from moving
1012 references to variable arrays below the code
1013 that deletes (pops) the arrays. */
1014 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1015 gen_rtx_MEM (BLKmode,
1016 gen_rtx_SCRATCH (VOIDmode))));
1017 emit_insn (gen_rtx_CLOBBER (VOIDmode,
1018 gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
1026 emit_insn (fcn (stack_pointer_rtx, sa));
1029 emit_insn_after (seq, after);
1032 emit_insn (fcn (stack_pointer_rtx, sa));
1035 #ifdef SETJMP_VIA_SAVE_AREA
1036 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1037 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1038 platforms, the dynamic stack space used can corrupt the original
1039 frame, thus causing a crash if a longjmp unwinds to it. */
1042 optimize_save_area_alloca (rtx insns)
1046 for (insn = insns; insn; insn = NEXT_INSN(insn))
1050 if (GET_CODE (insn) != INSN)
1053 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1055 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1058 if (!current_function_calls_setjmp)
1060 rtx pat = PATTERN (insn);
1062 /* If we do not see the note in a pattern matching
1063 these precise characteristics, we did something
1064 entirely wrong in allocate_dynamic_stack_space.
1066 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1067 was defined on a machine where stacks grow towards higher
1070 Right now only supported port with stack that grow upward
1071 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1072 if (GET_CODE (pat) != SET
1073 || SET_DEST (pat) != stack_pointer_rtx
1074 || GET_CODE (SET_SRC (pat)) != MINUS
1075 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1078 /* This will now be transformed into a (set REG REG)
1079 so we can just blow away all the other notes. */
1080 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1081 REG_NOTES (insn) = NULL_RTX;
1085 /* setjmp was called, we must remove the REG_SAVE_AREA
1086 note so that later passes do not get confused by its
1088 if (note == REG_NOTES (insn))
1090 REG_NOTES (insn) = XEXP (note, 1);
1096 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1097 if (XEXP (srch, 1) == note)
1100 if (srch == NULL_RTX)
1103 XEXP (srch, 1) = XEXP (note, 1);
1106 /* Once we've seen the note of interest, we need not look at
1107 the rest of them. */
1112 #endif /* SETJMP_VIA_SAVE_AREA */
1114 /* Return an rtx representing the address of an area of memory dynamically
1115 pushed on the stack. This region of memory is always aligned to
1116 a multiple of BIGGEST_ALIGNMENT.
1118 Any required stack pointer alignment is preserved.
1120 SIZE is an rtx representing the size of the area.
1121 TARGET is a place in which the address can be placed.
1123 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1126 allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
1128 #ifdef SETJMP_VIA_SAVE_AREA
1129 rtx setjmpless_size = NULL_RTX;
1132 /* If we're asking for zero bytes, it doesn't matter what we point
1133 to since we can't dereference it. But return a reasonable
1135 if (size == const0_rtx)
1136 return virtual_stack_dynamic_rtx;
1138 /* Otherwise, show we're calling alloca or equivalent. */
1139 current_function_calls_alloca = 1;
1141 /* Ensure the size is in the proper mode. */
1142 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1143 size = convert_to_mode (Pmode, size, 1);
1145 /* We can't attempt to minimize alignment necessary, because we don't
1146 know the final value of preferred_stack_boundary yet while executing
1148 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1150 /* We will need to ensure that the address we return is aligned to
1151 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1152 always know its final value at this point in the compilation (it
1153 might depend on the size of the outgoing parameter lists, for
1154 example), so we must align the value to be returned in that case.
1155 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
1156 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1157 We must also do an alignment operation on the returned value if
1158 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1160 If we have to align, we must leave space in SIZE for the hole
1161 that might result from the alignment operation. */
1163 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
1164 #define MUST_ALIGN 1
1166 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1171 = force_operand (plus_constant (size,
1172 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1175 #ifdef SETJMP_VIA_SAVE_AREA
1176 /* If setjmp restores regs from a save area in the stack frame,
1177 avoid clobbering the reg save area. Note that the offset of
1178 virtual_incoming_args_rtx includes the preallocated stack args space.
1179 It would be no problem to clobber that, but it's on the wrong side
1180 of the old save area. */
1183 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1184 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1186 if (!current_function_calls_setjmp)
1188 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1190 /* See optimize_save_area_alloca to understand what is being
1193 /* ??? Code below assumes that the save area needs maximal
1194 alignment. This constraint may be too strong. */
1195 if (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1198 if (GET_CODE (size) == CONST_INT)
1200 HOST_WIDE_INT new = INTVAL (size) / align * align;
1202 if (INTVAL (size) != new)
1203 setjmpless_size = GEN_INT (new);
1205 setjmpless_size = size;
1209 /* Since we know overflow is not possible, we avoid using
1210 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1211 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1212 GEN_INT (align), NULL_RTX, 1);
1213 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1214 GEN_INT (align), NULL_RTX, 1);
1216 /* Our optimization works based upon being able to perform a simple
1217 transformation of this RTL into a (set REG REG) so make sure things
1218 did in fact end up in a REG. */
1219 if (!register_operand (setjmpless_size, Pmode))
1220 setjmpless_size = force_reg (Pmode, setjmpless_size);
1223 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1224 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1226 #endif /* SETJMP_VIA_SAVE_AREA */
1228 /* Round the size to a multiple of the required stack alignment.
1229 Since the stack if presumed to be rounded before this allocation,
1230 this will maintain the required alignment.
1232 If the stack grows downward, we could save an insn by subtracting
1233 SIZE from the stack pointer and then aligning the stack pointer.
1234 The problem with this is that the stack pointer may be unaligned
1235 between the execution of the subtraction and alignment insns and
1236 some machines do not allow this. Even on those that do, some
1237 signal handlers malfunction if a signal should occur between those
1238 insns. Since this is an extremely rare event, we have no reliable
1239 way of knowing which systems have this problem. So we avoid even
1240 momentarily mis-aligning the stack. */
1242 /* If we added a variable amount to SIZE,
1243 we can no longer assume it is aligned. */
1244 #if !defined (SETJMP_VIA_SAVE_AREA)
1245 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1247 size = round_push (size);
1249 do_pending_stack_adjust ();
1251 /* We ought to be called always on the toplevel and stack ought to be aligned
1253 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1256 /* If needed, check that we have the required amount of stack. Take into
1257 account what has already been checked. */
1258 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1259 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1261 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */
1262 if (target == 0 || GET_CODE (target) != REG
1263 || REGNO (target) < FIRST_PSEUDO_REGISTER
1264 || GET_MODE (target) != Pmode)
1265 target = gen_reg_rtx (Pmode);
1267 mark_reg_pointer (target, known_align);
1269 /* Perform the required allocation from the stack. Some systems do
1270 this differently than simply incrementing/decrementing from the
1271 stack pointer, such as acquiring the space by calling malloc(). */
1272 #ifdef HAVE_allocate_stack
1273 if (HAVE_allocate_stack)
1275 enum machine_mode mode = STACK_SIZE_MODE;
1276 insn_operand_predicate_fn pred;
1278 /* We don't have to check against the predicate for operand 0 since
1279 TARGET is known to be a pseudo of the proper mode, which must
1280 be valid for the operand. For operand 1, convert to the
1281 proper mode and validate. */
1282 if (mode == VOIDmode)
1283 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode;
1285 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1286 if (pred && ! ((*pred) (size, mode)))
1287 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1));
1289 emit_insn (gen_allocate_stack (target, size));
1294 #ifndef STACK_GROWS_DOWNWARD
1295 emit_move_insn (target, virtual_stack_dynamic_rtx);
1298 /* Check stack bounds if necessary. */
1299 if (current_function_limit_stack)
1302 rtx space_available = gen_label_rtx ();
1303 #ifdef STACK_GROWS_DOWNWARD
1304 available = expand_binop (Pmode, sub_optab,
1305 stack_pointer_rtx, stack_limit_rtx,
1306 NULL_RTX, 1, OPTAB_WIDEN);
1308 available = expand_binop (Pmode, sub_optab,
1309 stack_limit_rtx, stack_pointer_rtx,
1310 NULL_RTX, 1, OPTAB_WIDEN);
1312 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1316 emit_insn (gen_trap ());
1319 error ("stack limits not supported on this target");
1321 emit_label (space_available);
1324 anti_adjust_stack (size);
1325 #ifdef SETJMP_VIA_SAVE_AREA
1326 if (setjmpless_size != NULL_RTX)
1328 rtx note_target = get_last_insn ();
1330 REG_NOTES (note_target)
1331 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1332 REG_NOTES (note_target));
1334 #endif /* SETJMP_VIA_SAVE_AREA */
1336 #ifdef STACK_GROWS_DOWNWARD
1337 emit_move_insn (target, virtual_stack_dynamic_rtx);
1343 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1344 but we know it can't. So add ourselves and then do
1346 target = expand_binop (Pmode, add_optab, target,
1347 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1348 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1349 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1350 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1352 target = expand_mult (Pmode, target,
1353 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1357 /* Record the new stack level for nonlocal gotos. */
1358 if (nonlocal_goto_handler_slots != 0)
1359 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1364 /* A front end may want to override GCC's stack checking by providing a
1365 run-time routine to call to check the stack, so provide a mechanism for
1366 calling that routine. */
1368 static GTY(()) rtx stack_check_libfunc;
1371 set_stack_check_libfunc (rtx libfunc)
1373 stack_check_libfunc = libfunc;
1376 /* Emit one stack probe at ADDRESS, an address within the stack. */
1379 emit_stack_probe (rtx address)
1381 rtx memref = gen_rtx_MEM (word_mode, address);
1383 MEM_VOLATILE_P (memref) = 1;
1385 if (STACK_CHECK_PROBE_LOAD)
1386 emit_move_insn (gen_reg_rtx (word_mode), memref);
1388 emit_move_insn (memref, const0_rtx);
1391 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1392 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1393 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1394 subtract from the stack. If SIZE is constant, this is done
1395 with a fixed number of probes. Otherwise, we must make a loop. */
1397 #ifdef STACK_GROWS_DOWNWARD
1398 #define STACK_GROW_OP MINUS
1400 #define STACK_GROW_OP PLUS
1404 probe_stack_range (HOST_WIDE_INT first, rtx size)
1406 /* First ensure SIZE is Pmode. */
1407 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1408 size = convert_to_mode (Pmode, size, 1);
1410 /* Next see if the front end has set up a function for us to call to
1412 if (stack_check_libfunc != 0)
1414 rtx addr = memory_address (QImode,
1415 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1417 plus_constant (size, first)));
1419 addr = convert_memory_address (ptr_mode, addr);
1420 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr,
1424 /* Next see if we have an insn to check the stack. Use it if so. */
1425 #ifdef HAVE_check_stack
1426 else if (HAVE_check_stack)
1428 insn_operand_predicate_fn pred;
1430 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1432 plus_constant (size, first)),
1435 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1436 if (pred && ! ((*pred) (last_addr, Pmode)))
1437 last_addr = copy_to_mode_reg (Pmode, last_addr);
1439 emit_insn (gen_check_stack (last_addr));
1443 /* If we have to generate explicit probes, see if we have a constant
1444 small number of them to generate. If so, that's the easy case. */
1445 else if (GET_CODE (size) == CONST_INT
1446 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1448 HOST_WIDE_INT offset;
1450 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1451 for values of N from 1 until it exceeds LAST. If only one
1452 probe is needed, this will not generate any code. Then probe
1454 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1455 offset < INTVAL (size);
1456 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1457 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1461 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1463 plus_constant (size, first)));
1466 /* In the variable case, do the same as above, but in a loop. We emit loop
1467 notes so that loop optimization can be done. */
1471 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1473 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1476 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1478 plus_constant (size, first)),
1480 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1481 rtx loop_lab = gen_label_rtx ();
1482 rtx test_lab = gen_label_rtx ();
1483 rtx end_lab = gen_label_rtx ();
1486 if (GET_CODE (test_addr) != REG
1487 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1488 test_addr = force_reg (Pmode, test_addr);
1490 emit_note (NOTE_INSN_LOOP_BEG);
1491 emit_jump (test_lab);
1493 emit_label (loop_lab);
1494 emit_stack_probe (test_addr);
1496 emit_note (NOTE_INSN_LOOP_CONT);
1498 #ifdef STACK_GROWS_DOWNWARD
1499 #define CMP_OPCODE GTU
1500 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1503 #define CMP_OPCODE LTU
1504 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1508 if (temp != test_addr)
1511 emit_label (test_lab);
1512 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1513 NULL_RTX, Pmode, 1, loop_lab);
1514 emit_jump (end_lab);
1515 emit_note (NOTE_INSN_LOOP_END);
1516 emit_label (end_lab);
1518 emit_stack_probe (last_addr);
1522 /* Return an rtx representing the register or memory location
1523 in which a scalar value of data type VALTYPE
1524 was returned by a function call to function FUNC.
1525 FUNC is a FUNCTION_DECL node if the precise function is known,
1527 OUTGOING is 1 if on a machine with register windows this function
1528 should return the register in which the function will put its result
1532 hard_function_value (tree valtype, tree func ATTRIBUTE_UNUSED,
1533 int outgoing ATTRIBUTE_UNUSED)
1537 #ifdef FUNCTION_OUTGOING_VALUE
1539 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1542 val = FUNCTION_VALUE (valtype, func);
1544 if (GET_CODE (val) == REG
1545 && GET_MODE (val) == BLKmode)
1547 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1548 enum machine_mode tmpmode;
1550 /* int_size_in_bytes can return -1. We don't need a check here
1551 since the value of bytes will be large enough that no mode
1552 will match and we will abort later in this function. */
1554 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1555 tmpmode != VOIDmode;
1556 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1558 /* Have we found a large enough mode? */
1559 if (GET_MODE_SIZE (tmpmode) >= bytes)
1563 /* No suitable mode found. */
1564 if (tmpmode == VOIDmode)
1567 PUT_MODE (val, tmpmode);
1572 /* Return an rtx representing the register or memory location
1573 in which a scalar value of mode MODE was returned by a library call. */
1576 hard_libcall_value (enum machine_mode mode)
1578 return LIBCALL_VALUE (mode);
1581 /* Look up the tree code for a given rtx code
1582 to provide the arithmetic operation for REAL_ARITHMETIC.
1583 The function returns an int because the caller may not know
1584 what `enum tree_code' means. */
1587 rtx_to_tree_code (enum rtx_code code)
1589 enum tree_code tcode;
1612 tcode = LAST_AND_UNUSED_TREE_CODE;
1615 return ((int) tcode);
1618 #include "gt-explow.h"