1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
32 #include "hard-reg-set.h"
33 #include "insn-config.h"
35 #include "insn-flags.h"
36 #include "insn-codes.h"
38 #if !defined PREFERRED_STACK_BOUNDARY && defined STACK_BOUNDARY
39 #define PREFERRED_STACK_BOUNDARY STACK_BOUNDARY
42 static rtx break_out_memory_refs PARAMS ((rtx));
43 static void emit_stack_probe PARAMS ((rtx));
46 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
49 trunc_int_for_mode (c, mode)
51 enum machine_mode mode;
53 int width = GET_MODE_BITSIZE (mode);
55 /* We clear out all bits that don't belong in MODE, unless they and our
56 sign bit are all one. So we get either a reasonable negative
57 value or a reasonable unsigned value. */
59 if (width < HOST_BITS_PER_WIDE_INT
60 && ((c & ((HOST_WIDE_INT) (-1) << (width - 1)))
61 != ((HOST_WIDE_INT) (-1) << (width - 1))))
62 c &= ((HOST_WIDE_INT) 1 << width) - 1;
64 /* If this would be an entire word for the target, but is not for
65 the host, then sign-extend on the host so that the number will look
66 the same way on the host that it would on the target.
68 For example, when building a 64 bit alpha hosted 32 bit sparc
69 targeted compiler, then we want the 32 bit unsigned value -1 to be
70 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
71 The later confuses the sparc backend. */
73 if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT
74 && BITS_PER_WORD == width
75 && (c & ((HOST_WIDE_INT) 1 << (width - 1))))
76 c |= ((HOST_WIDE_INT) (-1) << width);
81 /* Return an rtx for the sum of X and the integer C.
83 This function should be used via the `plus_constant' macro. */
86 plus_constant_wide (x, c)
88 register HOST_WIDE_INT c;
90 register RTX_CODE code;
91 register enum machine_mode mode;
105 return GEN_INT (INTVAL (x) + c);
109 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
110 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
111 HOST_WIDE_INT l2 = c;
112 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
113 HOST_WIDE_INT lv, hv;
115 add_double (l1, h1, l2, h2, &lv, &hv);
117 return immed_double_const (lv, hv, VOIDmode);
121 /* If this is a reference to the constant pool, try replacing it with
122 a reference to a new constant. If the resulting address isn't
123 valid, don't return it because we have no way to validize it. */
124 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
125 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
127 /* Any rtl we create here must go in a saveable obstack, since
128 we might have been called from within combine. */
129 push_obstacks_nochange ();
130 rtl_in_saveable_obstack ();
132 = force_const_mem (GET_MODE (x),
133 plus_constant (get_pool_constant (XEXP (x, 0)),
136 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
142 /* If adding to something entirely constant, set a flag
143 so that we can add a CONST around the result. */
154 /* The interesting case is adding the integer to a sum.
155 Look for constant term in the sum and combine
156 with C. For an integer constant term, we make a combined
157 integer. For a constant term that is not an explicit integer,
158 we cannot really combine, but group them together anyway.
160 Restart or use a recursive call in case the remaining operand is
161 something that we handle specially, such as a SYMBOL_REF.
163 We may not immediately return from the recursive call here, lest
164 all_constant gets lost. */
166 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
168 c += INTVAL (XEXP (x, 1));
170 if (GET_MODE (x) != VOIDmode)
171 c = trunc_int_for_mode (c, GET_MODE (x));
176 else if (CONSTANT_P (XEXP (x, 0)))
178 x = gen_rtx_PLUS (mode,
179 plus_constant (XEXP (x, 0), c),
183 else if (CONSTANT_P (XEXP (x, 1)))
185 x = gen_rtx_PLUS (mode,
187 plus_constant (XEXP (x, 1), c));
197 x = gen_rtx_PLUS (mode, x, GEN_INT (c));
199 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
201 else if (all_constant)
202 return gen_rtx_CONST (mode, x);
207 /* This is the same as `plus_constant', except that it handles LO_SUM.
209 This function should be used via the `plus_constant_for_output' macro. */
212 plus_constant_for_output_wide (x, c)
214 register HOST_WIDE_INT c;
216 register enum machine_mode mode = GET_MODE (x);
218 if (GET_CODE (x) == LO_SUM)
219 return gen_rtx_LO_SUM (mode, XEXP (x, 0),
220 plus_constant_for_output (XEXP (x, 1), c));
223 return plus_constant (x, c);
226 /* If X is a sum, return a new sum like X but lacking any constant terms.
227 Add all the removed constant terms into *CONSTPTR.
228 X itself is not altered. The result != X if and only if
229 it is not isomorphic to X. */
232 eliminate_constant_term (x, constptr)
239 if (GET_CODE (x) != PLUS)
242 /* First handle constants appearing at this level explicitly. */
243 if (GET_CODE (XEXP (x, 1)) == CONST_INT
244 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
246 && GET_CODE (tem) == CONST_INT)
249 return eliminate_constant_term (XEXP (x, 0), constptr);
253 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
254 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
255 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
256 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
258 && GET_CODE (tem) == CONST_INT)
261 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
267 /* Returns the insn that next references REG after INSN, or 0
268 if REG is clobbered before next referenced or we cannot find
269 an insn that references REG in a straight-line piece of code. */
272 find_next_ref (reg, insn)
278 for (insn = NEXT_INSN (insn); insn; insn = next)
280 next = NEXT_INSN (insn);
281 if (GET_CODE (insn) == NOTE)
283 if (GET_CODE (insn) == CODE_LABEL
284 || GET_CODE (insn) == BARRIER)
286 if (GET_CODE (insn) == INSN
287 || GET_CODE (insn) == JUMP_INSN
288 || GET_CODE (insn) == CALL_INSN)
290 if (reg_set_p (reg, insn))
292 if (reg_mentioned_p (reg, PATTERN (insn)))
294 if (GET_CODE (insn) == JUMP_INSN)
296 if (simplejump_p (insn))
297 next = JUMP_LABEL (insn);
301 if (GET_CODE (insn) == CALL_INSN
302 && REGNO (reg) < FIRST_PSEUDO_REGISTER
303 && call_used_regs[REGNO (reg)])
312 /* Return an rtx for the size in bytes of the value of EXP. */
318 tree size = size_in_bytes (TREE_TYPE (exp));
320 if (TREE_CODE (size) != INTEGER_CST
321 && contains_placeholder_p (size))
322 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
324 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype),
325 EXPAND_MEMORY_USE_BAD);
328 /* Return a copy of X in which all memory references
329 and all constants that involve symbol refs
330 have been replaced with new temporary registers.
331 Also emit code to load the memory locations and constants
332 into those registers.
334 If X contains no such constants or memory references,
335 X itself (not a copy) is returned.
337 If a constant is found in the address that is not a legitimate constant
338 in an insn, it is left alone in the hope that it might be valid in the
341 X may contain no arithmetic except addition, subtraction and multiplication.
342 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
345 break_out_memory_refs (x)
348 if (GET_CODE (x) == MEM
349 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
350 && GET_MODE (x) != VOIDmode))
351 x = force_reg (GET_MODE (x), x);
352 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
353 || GET_CODE (x) == MULT)
355 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
356 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
358 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
359 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
365 #ifdef POINTERS_EXTEND_UNSIGNED
367 /* Given X, a memory address in ptr_mode, convert it to an address
368 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
369 the fact that pointers are not allowed to overflow by commuting arithmetic
370 operations over conversions so that address arithmetic insns can be
374 convert_memory_address (to_mode, x)
375 enum machine_mode to_mode;
378 enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode;
381 /* Here we handle some special cases. If none of them apply, fall through
382 to the default case. */
383 switch (GET_CODE (x))
390 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0));
391 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
395 temp = gen_rtx_SYMBOL_REF (to_mode, XSTR (x, 0));
396 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
397 CONSTANT_POOL_ADDRESS_P (temp) = CONSTANT_POOL_ADDRESS_P (x);
401 return gen_rtx_CONST (to_mode,
402 convert_memory_address (to_mode, XEXP (x, 0)));
406 /* For addition the second operand is a small constant, we can safely
407 permute the conversion and addition operation. We can always safely
408 permute them if we are making the address narrower. In addition,
409 always permute the operations if this is a constant. */
410 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
411 || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT
412 && (INTVAL (XEXP (x, 1)) + 20000 < 40000
413 || CONSTANT_P (XEXP (x, 0)))))
414 return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
415 convert_memory_address (to_mode, XEXP (x, 0)),
416 convert_memory_address (to_mode, XEXP (x, 1)));
423 return convert_modes (to_mode, from_mode,
424 x, POINTERS_EXTEND_UNSIGNED);
428 /* Given a memory address or facsimile X, construct a new address,
429 currently equivalent, that is stable: future stores won't change it.
431 X must be composed of constants, register and memory references
432 combined with addition, subtraction and multiplication:
433 in other words, just what you can get from expand_expr if sum_ok is 1.
435 Works by making copies of all regs and memory locations used
436 by X and combining them the same way X does.
437 You could also stabilize the reference to this address
438 by copying the address to a register with copy_to_reg;
439 but then you wouldn't get indexed addressing in the reference. */
445 if (GET_CODE (x) == REG)
447 if (REGNO (x) != FRAME_POINTER_REGNUM
448 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
449 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
454 else if (GET_CODE (x) == MEM)
456 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
457 || GET_CODE (x) == MULT)
459 register rtx op0 = copy_all_regs (XEXP (x, 0));
460 register rtx op1 = copy_all_regs (XEXP (x, 1));
461 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
462 x = gen_rtx_fmt_ee (GET_CODE (x), Pmode, op0, op1);
467 /* Return something equivalent to X but valid as a memory address
468 for something of mode MODE. When X is not itself valid, this
469 works by copying X or subexpressions of it into registers. */
472 memory_address (mode, x)
473 enum machine_mode mode;
476 register rtx oldx = x;
478 if (GET_CODE (x) == ADDRESSOF)
481 #ifdef POINTERS_EXTEND_UNSIGNED
482 if (GET_MODE (x) == ptr_mode)
483 x = convert_memory_address (Pmode, x);
486 /* By passing constant addresses thru registers
487 we get a chance to cse them. */
488 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
489 x = force_reg (Pmode, x);
491 /* Accept a QUEUED that refers to a REG
492 even though that isn't a valid address.
493 On attempting to put this in an insn we will call protect_from_queue
494 which will turn it into a REG, which is valid. */
495 else if (GET_CODE (x) == QUEUED
496 && GET_CODE (QUEUED_VAR (x)) == REG)
499 /* We get better cse by rejecting indirect addressing at this stage.
500 Let the combiner create indirect addresses where appropriate.
501 For now, generate the code so that the subexpressions useful to share
502 are visible. But not if cse won't be done! */
505 if (! cse_not_expected && GET_CODE (x) != REG)
506 x = break_out_memory_refs (x);
508 /* At this point, any valid address is accepted. */
509 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
511 /* If it was valid before but breaking out memory refs invalidated it,
512 use it the old way. */
513 if (memory_address_p (mode, oldx))
516 /* Perform machine-dependent transformations on X
517 in certain cases. This is not necessary since the code
518 below can handle all possible cases, but machine-dependent
519 transformations can make better code. */
520 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
522 /* PLUS and MULT can appear in special ways
523 as the result of attempts to make an address usable for indexing.
524 Usually they are dealt with by calling force_operand, below.
525 But a sum containing constant terms is special
526 if removing them makes the sum a valid address:
527 then we generate that address in a register
528 and index off of it. We do this because it often makes
529 shorter code, and because the addresses thus generated
530 in registers often become common subexpressions. */
531 if (GET_CODE (x) == PLUS)
533 rtx constant_term = const0_rtx;
534 rtx y = eliminate_constant_term (x, &constant_term);
535 if (constant_term == const0_rtx
536 || ! memory_address_p (mode, y))
537 x = force_operand (x, NULL_RTX);
540 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
541 if (! memory_address_p (mode, y))
542 x = force_operand (x, NULL_RTX);
548 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
549 x = force_operand (x, NULL_RTX);
551 /* If we have a register that's an invalid address,
552 it must be a hard reg of the wrong class. Copy it to a pseudo. */
553 else if (GET_CODE (x) == REG)
556 /* Last resort: copy the value to a register, since
557 the register is a valid address. */
559 x = force_reg (Pmode, x);
566 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
567 /* Don't copy an addr via a reg if it is one of our stack slots. */
568 && ! (GET_CODE (x) == PLUS
569 && (XEXP (x, 0) == virtual_stack_vars_rtx
570 || XEXP (x, 0) == virtual_incoming_args_rtx)))
572 if (general_operand (x, Pmode))
573 x = force_reg (Pmode, x);
575 x = force_operand (x, NULL_RTX);
581 /* If we didn't change the address, we are done. Otherwise, mark
582 a reg as a pointer if we have REG or REG + CONST_INT. */
585 else if (GET_CODE (x) == REG)
586 mark_reg_pointer (x, BITS_PER_UNIT);
587 else if (GET_CODE (x) == PLUS
588 && GET_CODE (XEXP (x, 0)) == REG
589 && GET_CODE (XEXP (x, 1)) == CONST_INT)
590 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
592 /* OLDX may have been the address on a temporary. Update the address
593 to indicate that X is now used. */
594 update_temp_slot_address (oldx, x);
599 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
602 memory_address_noforce (mode, x)
603 enum machine_mode mode;
606 int ambient_force_addr = flag_force_addr;
610 val = memory_address (mode, x);
611 flag_force_addr = ambient_force_addr;
615 /* Convert a mem ref into one with a valid memory address.
616 Pass through anything else unchanged. */
622 if (GET_CODE (ref) != MEM)
624 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
626 /* Don't alter REF itself, since that is probably a stack slot. */
627 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
630 /* Return a modified copy of X with its memory address copied
631 into a temporary register to protect it from side effects.
632 If X is not a MEM, it is returned unchanged (and not copied).
633 Perhaps even if it is a MEM, if there is no need to change it. */
640 if (GET_CODE (x) != MEM)
643 if (rtx_unstable_p (addr))
645 rtx temp = copy_all_regs (addr);
648 if (GET_CODE (temp) != REG)
649 temp = copy_to_reg (temp);
650 mem = gen_rtx_MEM (GET_MODE (x), temp);
652 /* Mark returned memref with in_struct if it's in an array or
653 structure. Copy everything else from original memref. */
655 MEM_COPY_ATTRIBUTES (mem, x);
656 if (GET_CODE (addr) == PLUS)
657 MEM_SET_IN_STRUCT_P (mem, 1);
664 /* Copy the value or contents of X to a new temp reg and return that reg. */
670 register rtx temp = gen_reg_rtx (GET_MODE (x));
672 /* If not an operand, must be an address with PLUS and MULT so
673 do the computation. */
674 if (! general_operand (x, VOIDmode))
675 x = force_operand (x, temp);
678 emit_move_insn (temp, x);
683 /* Like copy_to_reg but always give the new register mode Pmode
684 in case X is a constant. */
690 return copy_to_mode_reg (Pmode, x);
693 /* Like copy_to_reg but always give the new register mode MODE
694 in case X is a constant. */
697 copy_to_mode_reg (mode, x)
698 enum machine_mode mode;
701 register rtx temp = gen_reg_rtx (mode);
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);
708 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
711 emit_move_insn (temp, x);
715 /* Load X into a register if it is not already one.
716 Use mode MODE for the register.
717 X should be valid for mode MODE, but it may be a constant which
718 is valid for all integer modes; that's why caller must specify MODE.
720 The caller must not alter the value in the register we return,
721 since we mark it as a "constant" register. */
725 enum machine_mode mode;
728 register rtx temp, insn, set;
730 if (GET_CODE (x) == REG)
733 temp = gen_reg_rtx (mode);
735 if (! general_operand (x, mode))
736 x = force_operand (x, NULL_RTX);
738 insn = emit_move_insn (temp, x);
740 /* Let optimizers know that TEMP's value never changes
741 and that X can be substituted for it. Don't get confused
742 if INSN set something else (such as a SUBREG of TEMP). */
744 && (set = single_set (insn)) != 0
745 && SET_DEST (set) == temp)
747 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
752 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL, x, REG_NOTES (insn));
757 /* If X is a memory ref, copy its contents to a new temp reg and return
758 that reg. Otherwise, return X. */
765 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
767 temp = gen_reg_rtx (GET_MODE (x));
768 emit_move_insn (temp, x);
772 /* Copy X to TARGET (if it's nonzero and a reg)
773 or to a new temp reg and return that reg.
774 MODE is the mode to use for X in case it is a constant. */
777 copy_to_suggested_reg (x, target, mode)
779 enum machine_mode mode;
783 if (target && GET_CODE (target) == REG)
786 temp = gen_reg_rtx (mode);
788 emit_move_insn (temp, x);
792 /* Return the mode to use to store a scalar of TYPE and MODE.
793 PUNSIGNEDP points to the signedness of the type and may be adjusted
794 to show what signedness to use on extension operations.
796 FOR_CALL is non-zero if this call is promoting args for a call. */
799 promote_mode (type, mode, punsignedp, for_call)
801 enum machine_mode mode;
803 int for_call ATTRIBUTE_UNUSED;
805 enum tree_code code = TREE_CODE (type);
806 int unsignedp = *punsignedp;
808 #ifdef PROMOTE_FOR_CALL_ONLY
816 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
817 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
818 PROMOTE_MODE (mode, unsignedp, type);
822 #ifdef POINTERS_EXTEND_UNSIGNED
826 unsignedp = POINTERS_EXTEND_UNSIGNED;
834 *punsignedp = unsignedp;
838 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
839 This pops when ADJUST is positive. ADJUST need not be constant. */
842 adjust_stack (adjust)
846 adjust = protect_from_queue (adjust, 0);
848 if (adjust == const0_rtx)
851 /* We expect all variable sized adjustments to be multiple of
852 PREFERRED_STACK_BOUNDARY. */
853 if (GET_CODE (adjust) == CONST_INT)
854 stack_pointer_delta -= INTVAL (adjust);
856 temp = expand_binop (Pmode,
857 #ifdef STACK_GROWS_DOWNWARD
862 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
865 if (temp != stack_pointer_rtx)
866 emit_move_insn (stack_pointer_rtx, temp);
869 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
870 This pushes when ADJUST is positive. ADJUST need not be constant. */
873 anti_adjust_stack (adjust)
877 adjust = protect_from_queue (adjust, 0);
879 if (adjust == const0_rtx)
882 /* We expect all variable sized adjustments to be multiple of
883 PREFERRED_STACK_BOUNDARY. */
884 if (GET_CODE (adjust) == CONST_INT)
885 stack_pointer_delta += INTVAL (adjust);
887 temp = expand_binop (Pmode,
888 #ifdef STACK_GROWS_DOWNWARD
893 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
896 if (temp != stack_pointer_rtx)
897 emit_move_insn (stack_pointer_rtx, temp);
900 /* Round the size of a block to be pushed up to the boundary required
901 by this machine. SIZE is the desired size, which need not be constant. */
907 #ifdef PREFERRED_STACK_BOUNDARY
908 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
911 if (GET_CODE (size) == CONST_INT)
913 int new = (INTVAL (size) + align - 1) / align * align;
914 if (INTVAL (size) != new)
915 size = GEN_INT (new);
919 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
920 but we know it can't. So add ourselves and then do
922 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
923 NULL_RTX, 1, OPTAB_LIB_WIDEN);
924 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
926 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
928 #endif /* PREFERRED_STACK_BOUNDARY */
932 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
933 to a previously-created save area. If no save area has been allocated,
934 this function will allocate one. If a save area is specified, it
935 must be of the proper mode.
937 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
938 are emitted at the current position. */
941 emit_stack_save (save_level, psave, after)
942 enum save_level save_level;
947 /* The default is that we use a move insn and save in a Pmode object. */
948 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
949 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level);
951 /* See if this machine has anything special to do for this kind of save. */
954 #ifdef HAVE_save_stack_block
956 if (HAVE_save_stack_block)
957 fcn = gen_save_stack_block;
960 #ifdef HAVE_save_stack_function
962 if (HAVE_save_stack_function)
963 fcn = gen_save_stack_function;
966 #ifdef HAVE_save_stack_nonlocal
968 if (HAVE_save_stack_nonlocal)
969 fcn = gen_save_stack_nonlocal;
976 /* If there is no save area and we have to allocate one, do so. Otherwise
977 verify the save area is the proper mode. */
981 if (mode != VOIDmode)
983 if (save_level == SAVE_NONLOCAL)
984 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
986 *psave = sa = gen_reg_rtx (mode);
991 if (mode == VOIDmode || GET_MODE (sa) != mode)
1000 /* We must validize inside the sequence, to ensure that any instructions
1001 created by the validize call also get moved to the right place. */
1003 sa = validize_mem (sa);
1004 emit_insn (fcn (sa, stack_pointer_rtx));
1005 seq = gen_sequence ();
1007 emit_insn_after (seq, after);
1012 sa = validize_mem (sa);
1013 emit_insn (fcn (sa, stack_pointer_rtx));
1017 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1018 area made by emit_stack_save. If it is zero, we have nothing to do.
1020 Put any emitted insns after insn AFTER, if nonzero, otherwise at
1021 current position. */
1024 emit_stack_restore (save_level, sa, after)
1025 enum save_level save_level;
1029 /* The default is that we use a move insn. */
1030 rtx (*fcn) PARAMS ((rtx, rtx)) = gen_move_insn;
1032 /* See if this machine has anything special to do for this kind of save. */
1035 #ifdef HAVE_restore_stack_block
1037 if (HAVE_restore_stack_block)
1038 fcn = gen_restore_stack_block;
1041 #ifdef HAVE_restore_stack_function
1043 if (HAVE_restore_stack_function)
1044 fcn = gen_restore_stack_function;
1047 #ifdef HAVE_restore_stack_nonlocal
1049 if (HAVE_restore_stack_nonlocal)
1050 fcn = gen_restore_stack_nonlocal;
1058 sa = validize_mem (sa);
1065 emit_insn (fcn (stack_pointer_rtx, sa));
1066 seq = gen_sequence ();
1068 emit_insn_after (seq, after);
1071 emit_insn (fcn (stack_pointer_rtx, sa));
1074 #ifdef SETJMP_VIA_SAVE_AREA
1075 /* Optimize RTL generated by allocate_dynamic_stack_space for targets
1076 where SETJMP_VIA_SAVE_AREA is true. The problem is that on these
1077 platforms, the dynamic stack space used can corrupt the original
1078 frame, thus causing a crash if a longjmp unwinds to it. */
1081 optimize_save_area_alloca (insns)
1086 for (insn = insns; insn; insn = NEXT_INSN(insn))
1090 if (GET_CODE (insn) != INSN)
1093 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1095 if (REG_NOTE_KIND (note) != REG_SAVE_AREA)
1098 if (!current_function_calls_setjmp)
1100 rtx pat = PATTERN (insn);
1102 /* If we do not see the note in a pattern matching
1103 these precise characteristics, we did something
1104 entirely wrong in allocate_dynamic_stack_space.
1106 Note, one way this could happen is if SETJMP_VIA_SAVE_AREA
1107 was defined on a machine where stacks grow towards higher
1110 Right now only supported port with stack that grow upward
1111 is the HPPA and it does not define SETJMP_VIA_SAVE_AREA. */
1112 if (GET_CODE (pat) != SET
1113 || SET_DEST (pat) != stack_pointer_rtx
1114 || GET_CODE (SET_SRC (pat)) != MINUS
1115 || XEXP (SET_SRC (pat), 0) != stack_pointer_rtx)
1118 /* This will now be transformed into a (set REG REG)
1119 so we can just blow away all the other notes. */
1120 XEXP (SET_SRC (pat), 1) = XEXP (note, 0);
1121 REG_NOTES (insn) = NULL_RTX;
1125 /* setjmp was called, we must remove the REG_SAVE_AREA
1126 note so that later passes do not get confused by its
1128 if (note == REG_NOTES (insn))
1130 REG_NOTES (insn) = XEXP (note, 1);
1136 for (srch = REG_NOTES (insn); srch; srch = XEXP (srch, 1))
1137 if (XEXP (srch, 1) == note)
1140 if (srch == NULL_RTX)
1143 XEXP (srch, 1) = XEXP (note, 1);
1146 /* Once we've seen the note of interest, we need not look at
1147 the rest of them. */
1152 #endif /* SETJMP_VIA_SAVE_AREA */
1154 /* Return an rtx representing the address of an area of memory dynamically
1155 pushed on the stack. This region of memory is always aligned to
1156 a multiple of BIGGEST_ALIGNMENT.
1158 Any required stack pointer alignment is preserved.
1160 SIZE is an rtx representing the size of the area.
1161 TARGET is a place in which the address can be placed.
1163 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
1166 allocate_dynamic_stack_space (size, target, known_align)
1171 #ifdef SETJMP_VIA_SAVE_AREA
1172 rtx setjmpless_size = NULL_RTX;
1175 /* If we're asking for zero bytes, it doesn't matter what we point
1176 to since we can't dereference it. But return a reasonable
1178 if (size == const0_rtx)
1179 return virtual_stack_dynamic_rtx;
1181 /* Otherwise, show we're calling alloca or equivalent. */
1182 current_function_calls_alloca = 1;
1184 /* Ensure the size is in the proper mode. */
1185 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
1186 size = convert_to_mode (Pmode, size, 1);
1188 /* We can't attempt to minimize alignment necessary, because we don't
1189 know the final value of preferred_stack_boundary yet while executing
1191 #ifdef PREFERRED_STACK_BOUNDARY
1192 cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
1195 /* We will need to ensure that the address we return is aligned to
1196 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1197 always know its final value at this point in the compilation (it
1198 might depend on the size of the outgoing parameter lists, for
1199 example), so we must align the value to be returned in that case.
1200 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1201 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1202 We must also do an alignment operation on the returned value if
1203 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1205 If we have to align, we must leave space in SIZE for the hole
1206 that might result from the alignment operation. */
1208 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || ! defined (PREFERRED_STACK_BOUNDARY)
1209 #define MUST_ALIGN 1
1211 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1216 if (GET_CODE (size) == CONST_INT)
1217 size = GEN_INT (INTVAL (size)
1218 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1220 size = expand_binop (Pmode, add_optab, size,
1221 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1222 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1225 #ifdef SETJMP_VIA_SAVE_AREA
1226 /* If setjmp restores regs from a save area in the stack frame,
1227 avoid clobbering the reg save area. Note that the offset of
1228 virtual_incoming_args_rtx includes the preallocated stack args space.
1229 It would be no problem to clobber that, but it's on the wrong side
1230 of the old save area. */
1233 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1234 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1236 if (!current_function_calls_setjmp)
1238 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
1240 /* See optimize_save_area_alloca to understand what is being
1243 #if !defined(PREFERRED_STACK_BOUNDARY) || !defined(MUST_ALIGN) || (PREFERRED_STACK_BOUNDARY != BIGGEST_ALIGNMENT)
1244 /* If anyone creates a target with these characteristics, let them
1245 know that our optimization cannot work correctly in such a case. */
1249 if (GET_CODE (size) == CONST_INT)
1251 int new = INTVAL (size) / align * align;
1253 if (INTVAL (size) != new)
1254 setjmpless_size = GEN_INT (new);
1256 setjmpless_size = size;
1260 /* Since we know overflow is not possible, we avoid using
1261 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */
1262 setjmpless_size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
1263 GEN_INT (align), NULL_RTX, 1);
1264 setjmpless_size = expand_mult (Pmode, setjmpless_size,
1265 GEN_INT (align), NULL_RTX, 1);
1267 /* Our optimization works based upon being able to perform a simple
1268 transformation of this RTL into a (set REG REG) so make sure things
1269 did in fact end up in a REG. */
1270 if (!register_operand (setjmpless_size, Pmode))
1271 setjmpless_size = force_reg (Pmode, setjmpless_size);
1274 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1275 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1277 #endif /* SETJMP_VIA_SAVE_AREA */
1279 /* Round the size to a multiple of the required stack alignment.
1280 Since the stack if presumed to be rounded before this allocation,
1281 this will maintain the required alignment.
1283 If the stack grows downward, we could save an insn by subtracting
1284 SIZE from the stack pointer and then aligning the stack pointer.
1285 The problem with this is that the stack pointer may be unaligned
1286 between the execution of the subtraction and alignment insns and
1287 some machines do not allow this. Even on those that do, some
1288 signal handlers malfunction if a signal should occur between those
1289 insns. Since this is an extremely rare event, we have no reliable
1290 way of knowing which systems have this problem. So we avoid even
1291 momentarily mis-aligning the stack. */
1293 #ifdef PREFERRED_STACK_BOUNDARY
1294 /* If we added a variable amount to SIZE,
1295 we can no longer assume it is aligned. */
1296 #if !defined (SETJMP_VIA_SAVE_AREA)
1297 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
1299 size = round_push (size);
1302 do_pending_stack_adjust ();
1304 /* We ought to be called always on the toplevel and stack ought to be aligned
1306 #ifdef PREFERRED_STACK_BOUNDARY
1307 if (stack_pointer_delta % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))
1311 /* If needed, check that we have the required amount of stack. Take into
1312 account what has already been checked. */
1313 if (flag_stack_check && ! STACK_CHECK_BUILTIN)
1314 probe_stack_range (STACK_CHECK_MAX_FRAME_SIZE + STACK_CHECK_PROTECT, size);
1316 /* Don't use a TARGET that isn't a pseudo. */
1317 if (target == 0 || GET_CODE (target) != REG
1318 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1319 target = gen_reg_rtx (Pmode);
1321 mark_reg_pointer (target, known_align);
1323 /* Perform the required allocation from the stack. Some systems do
1324 this differently than simply incrementing/decrementing from the
1325 stack pointer, such as acquiring the space by calling malloc(). */
1326 #ifdef HAVE_allocate_stack
1327 if (HAVE_allocate_stack)
1329 enum machine_mode mode = STACK_SIZE_MODE;
1330 insn_operand_predicate_fn pred;
1332 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[0].predicate;
1333 if (pred && ! ((*pred) (target, Pmode)))
1334 #ifdef POINTERS_EXTEND_UNSIGNED
1335 target = convert_memory_address (Pmode, target);
1337 target = copy_to_mode_reg (Pmode, target);
1340 if (mode == VOIDmode)
1343 size = convert_modes (mode, ptr_mode, size, 1);
1344 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate;
1345 if (pred && ! ((*pred) (size, mode)))
1346 size = copy_to_mode_reg (mode, size);
1348 emit_insn (gen_allocate_stack (target, size));
1353 #ifndef STACK_GROWS_DOWNWARD
1354 emit_move_insn (target, virtual_stack_dynamic_rtx);
1356 size = convert_modes (Pmode, ptr_mode, size, 1);
1358 /* Check stack bounds if necessary. */
1359 if (current_function_limit_stack)
1362 rtx space_available = gen_label_rtx ();
1363 #ifdef STACK_GROWS_DOWNWARD
1364 available = expand_binop (Pmode, sub_optab,
1365 stack_pointer_rtx, stack_limit_rtx,
1366 NULL_RTX, 1, OPTAB_WIDEN);
1368 available = expand_binop (Pmode, sub_optab,
1369 stack_limit_rtx, stack_pointer_rtx,
1370 NULL_RTX, 1, OPTAB_WIDEN);
1372 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
1373 0, space_available);
1376 emit_insn (gen_trap ());
1379 error ("stack limits not supported on this target");
1381 emit_label (space_available);
1384 anti_adjust_stack (size);
1385 #ifdef SETJMP_VIA_SAVE_AREA
1386 if (setjmpless_size != NULL_RTX)
1388 rtx note_target = get_last_insn ();
1390 REG_NOTES (note_target)
1391 = gen_rtx_EXPR_LIST (REG_SAVE_AREA, setjmpless_size,
1392 REG_NOTES (note_target));
1394 #endif /* SETJMP_VIA_SAVE_AREA */
1395 #ifdef STACK_GROWS_DOWNWARD
1396 emit_move_insn (target, virtual_stack_dynamic_rtx);
1402 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1403 but we know it can't. So add ourselves and then do
1405 target = expand_binop (Pmode, add_optab, target,
1406 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1407 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1408 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1409 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1411 target = expand_mult (Pmode, target,
1412 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1416 /* Some systems require a particular insn to refer to the stack
1417 to make the pages exist. */
1420 emit_insn (gen_probe ());
1423 /* Record the new stack level for nonlocal gotos. */
1424 if (nonlocal_goto_handler_slots != 0)
1425 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1430 /* A front end may want to override GCC's stack checking by providing a
1431 run-time routine to call to check the stack, so provide a mechanism for
1432 calling that routine. */
1434 static rtx stack_check_libfunc;
1437 set_stack_check_libfunc (libfunc)
1440 stack_check_libfunc = libfunc;
1443 /* Emit one stack probe at ADDRESS, an address within the stack. */
1446 emit_stack_probe (address)
1449 rtx memref = gen_rtx_MEM (word_mode, address);
1451 MEM_VOLATILE_P (memref) = 1;
1453 if (STACK_CHECK_PROBE_LOAD)
1454 emit_move_insn (gen_reg_rtx (word_mode), memref);
1456 emit_move_insn (memref, const0_rtx);
1459 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1460 FIRST is a constant and size is a Pmode RTX. These are offsets from the
1461 current stack pointer. STACK_GROWS_DOWNWARD says whether to add or
1462 subtract from the stack. If SIZE is constant, this is done
1463 with a fixed number of probes. Otherwise, we must make a loop. */
1465 #ifdef STACK_GROWS_DOWNWARD
1466 #define STACK_GROW_OP MINUS
1468 #define STACK_GROW_OP PLUS
1472 probe_stack_range (first, size)
1473 HOST_WIDE_INT first;
1476 /* First see if the front end has set up a function for us to call to
1478 if (stack_check_libfunc != 0)
1479 emit_library_call (stack_check_libfunc, 0, VOIDmode, 1,
1480 memory_address (QImode,
1481 gen_rtx (STACK_GROW_OP, Pmode,
1483 plus_constant (size, first))),
1486 /* Next see if we have an insn to check the stack. Use it if so. */
1487 #ifdef HAVE_check_stack
1488 else if (HAVE_check_stack)
1490 insn_operand_predicate_fn pred;
1492 = force_operand (gen_rtx_STACK_GROW_OP (Pmode,
1494 plus_constant (size, first)),
1497 pred = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate;
1498 if (pred && ! ((*pred) (last_addr, Pmode)))
1499 last_addr = copy_to_mode_reg (Pmode, last_addr);
1501 emit_insn (gen_check_stack (last_addr));
1505 /* If we have to generate explicit probes, see if we have a constant
1506 small number of them to generate. If so, that's the easy case. */
1507 else if (GET_CODE (size) == CONST_INT
1508 && INTVAL (size) < 10 * STACK_CHECK_PROBE_INTERVAL)
1510 HOST_WIDE_INT offset;
1512 /* Start probing at FIRST + N * STACK_CHECK_PROBE_INTERVAL
1513 for values of N from 1 until it exceeds LAST. If only one
1514 probe is needed, this will not generate any code. Then probe
1516 for (offset = first + STACK_CHECK_PROBE_INTERVAL;
1517 offset < INTVAL (size);
1518 offset = offset + STACK_CHECK_PROBE_INTERVAL)
1519 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1523 emit_stack_probe (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1525 plus_constant (size, first)));
1528 /* In the variable case, do the same as above, but in a loop. We emit loop
1529 notes so that loop optimization can be done. */
1533 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1535 GEN_INT (first + STACK_CHECK_PROBE_INTERVAL)),
1538 = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
1540 plus_constant (size, first)),
1542 rtx incr = GEN_INT (STACK_CHECK_PROBE_INTERVAL);
1543 rtx loop_lab = gen_label_rtx ();
1544 rtx test_lab = gen_label_rtx ();
1545 rtx end_lab = gen_label_rtx ();
1548 if (GET_CODE (test_addr) != REG
1549 || REGNO (test_addr) < FIRST_PSEUDO_REGISTER)
1550 test_addr = force_reg (Pmode, test_addr);
1552 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1553 emit_jump (test_lab);
1555 emit_label (loop_lab);
1556 emit_stack_probe (test_addr);
1558 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1560 #ifdef STACK_GROWS_DOWNWARD
1561 #define CMP_OPCODE GTU
1562 temp = expand_binop (Pmode, sub_optab, test_addr, incr, test_addr,
1565 #define CMP_OPCODE LTU
1566 temp = expand_binop (Pmode, add_optab, test_addr, incr, test_addr,
1570 if (temp != test_addr)
1573 emit_label (test_lab);
1574 emit_cmp_and_jump_insns (test_addr, last_addr, CMP_OPCODE,
1575 NULL_RTX, Pmode, 1, 0, loop_lab);
1576 emit_jump (end_lab);
1577 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
1578 emit_label (end_lab);
1580 emit_stack_probe (last_addr);
1584 /* Return an rtx representing the register or memory location
1585 in which a scalar value of data type VALTYPE
1586 was returned by a function call to function FUNC.
1587 FUNC is a FUNCTION_DECL node if the precise function is known,
1589 OUTGOING is 1 if on a machine with register windows this function
1590 should return the register in which the function will put its result
1594 hard_function_value (valtype, func, outgoing)
1596 tree func ATTRIBUTE_UNUSED;
1597 int outgoing ATTRIBUTE_UNUSED;
1601 #ifdef FUNCTION_OUTGOING_VALUE
1603 val = FUNCTION_OUTGOING_VALUE (valtype, func);
1606 val = FUNCTION_VALUE (valtype, func);
1608 if (GET_CODE (val) == REG
1609 && GET_MODE (val) == BLKmode)
1611 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype);
1612 enum machine_mode tmpmode;
1614 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1615 tmpmode != VOIDmode;
1616 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1618 /* Have we found a large enough mode? */
1619 if (GET_MODE_SIZE (tmpmode) >= bytes)
1623 /* No suitable mode found. */
1624 if (tmpmode == VOIDmode)
1627 PUT_MODE (val, tmpmode);
1632 /* Return an rtx representing the register or memory location
1633 in which a scalar value of mode MODE was returned by a library call. */
1636 hard_libcall_value (mode)
1637 enum machine_mode mode;
1639 return LIBCALL_VALUE (mode);
1642 /* Look up the tree code for a given rtx code
1643 to provide the arithmetic operation for REAL_ARITHMETIC.
1644 The function returns an int because the caller may not know
1645 what `enum tree_code' means. */
1648 rtx_to_tree_code (code)
1651 enum tree_code tcode;
1674 tcode = LAST_AND_UNUSED_TREE_CODE;
1677 return ((int) tcode);