1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991, 1994, 1995 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
27 #include "hard-reg-set.h"
28 #include "insn-config.h"
30 #include "insn-flags.h"
31 #include "insn-codes.h"
33 static rtx break_out_memory_refs PROTO((rtx));
35 /* Return an rtx for the sum of X and the integer C.
37 This function should be used via the `plus_constant' macro. */
40 plus_constant_wide (x, c)
42 register HOST_WIDE_INT c;
44 register RTX_CODE code;
45 register enum machine_mode mode;
59 return GEN_INT (INTVAL (x) + c);
63 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
64 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
66 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
69 add_double (l1, h1, l2, h2, &lv, &hv);
71 return immed_double_const (lv, hv, VOIDmode);
75 /* If this is a reference to the constant pool, try replacing it with
76 a reference to a new constant. If the resulting address isn't
77 valid, don't return it because we have no way to validize it. */
78 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
79 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
82 = force_const_mem (GET_MODE (x),
83 plus_constant (get_pool_constant (XEXP (x, 0)),
85 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
91 /* If adding to something entirely constant, set a flag
92 so that we can add a CONST around the result. */
103 /* The interesting case is adding the integer to a sum.
104 Look for constant term in the sum and combine
105 with C. For an integer constant term, we make a combined
106 integer. For a constant term that is not an explicit integer,
107 we cannot really combine, but group them together anyway.
109 Use a recursive call in case the remaining operand is something
110 that we handle specially, such as a SYMBOL_REF. */
112 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
113 return plus_constant (XEXP (x, 0), c + INTVAL (XEXP (x, 1)));
114 else if (CONSTANT_P (XEXP (x, 0)))
115 return gen_rtx (PLUS, mode,
116 plus_constant (XEXP (x, 0), c),
118 else if (CONSTANT_P (XEXP (x, 1)))
119 return gen_rtx (PLUS, mode,
121 plus_constant (XEXP (x, 1), c));
125 x = gen_rtx (PLUS, mode, x, GEN_INT (c));
127 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
129 else if (all_constant)
130 return gen_rtx (CONST, mode, x);
135 /* This is the same as `plus_constant', except that it handles LO_SUM.
137 This function should be used via the `plus_constant_for_output' macro. */
140 plus_constant_for_output_wide (x, c)
142 register HOST_WIDE_INT c;
144 register RTX_CODE code = GET_CODE (x);
145 register enum machine_mode mode = GET_MODE (x);
146 int all_constant = 0;
148 if (GET_CODE (x) == LO_SUM)
149 return gen_rtx (LO_SUM, mode, XEXP (x, 0),
150 plus_constant_for_output (XEXP (x, 1), c));
153 return plus_constant (x, c);
156 /* If X is a sum, return a new sum like X but lacking any constant terms.
157 Add all the removed constant terms into *CONSTPTR.
158 X itself is not altered. The result != X if and only if
159 it is not isomorphic to X. */
162 eliminate_constant_term (x, constptr)
169 if (GET_CODE (x) != PLUS)
172 /* First handle constants appearing at this level explicitly. */
173 if (GET_CODE (XEXP (x, 1)) == CONST_INT
174 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
176 && GET_CODE (tem) == CONST_INT)
179 return eliminate_constant_term (XEXP (x, 0), constptr);
183 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
184 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
185 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
186 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
188 && GET_CODE (tem) == CONST_INT)
191 return gen_rtx (PLUS, GET_MODE (x), x0, x1);
197 /* Returns the insn that next references REG after INSN, or 0
198 if REG is clobbered before next referenced or we cannot find
199 an insn that references REG in a straight-line piece of code. */
202 find_next_ref (reg, insn)
208 for (insn = NEXT_INSN (insn); insn; insn = next)
210 next = NEXT_INSN (insn);
211 if (GET_CODE (insn) == NOTE)
213 if (GET_CODE (insn) == CODE_LABEL
214 || GET_CODE (insn) == BARRIER)
216 if (GET_CODE (insn) == INSN
217 || GET_CODE (insn) == JUMP_INSN
218 || GET_CODE (insn) == CALL_INSN)
220 if (reg_set_p (reg, insn))
222 if (reg_mentioned_p (reg, PATTERN (insn)))
224 if (GET_CODE (insn) == JUMP_INSN)
226 if (simplejump_p (insn))
227 next = JUMP_LABEL (insn);
231 if (GET_CODE (insn) == CALL_INSN
232 && REGNO (reg) < FIRST_PSEUDO_REGISTER
233 && call_used_regs[REGNO (reg)])
242 /* Return an rtx for the size in bytes of the value of EXP. */
248 tree size = size_in_bytes (TREE_TYPE (exp));
250 if (TREE_CODE (size) != INTEGER_CST
251 && contains_placeholder_p (size))
252 size = build (WITH_RECORD_EXPR, sizetype, size, exp);
254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0);
257 /* Return a copy of X in which all memory references
258 and all constants that involve symbol refs
259 have been replaced with new temporary registers.
260 Also emit code to load the memory locations and constants
261 into those registers.
263 If X contains no such constants or memory references,
264 X itself (not a copy) is returned.
266 If a constant is found in the address that is not a legitimate constant
267 in an insn, it is left alone in the hope that it might be valid in the
270 X may contain no arithmetic except addition, subtraction and multiplication.
271 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
274 break_out_memory_refs (x)
277 if (GET_CODE (x) == MEM
278 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
279 && GET_MODE (x) != VOIDmode))
280 x = force_reg (GET_MODE (x), x);
281 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
282 || GET_CODE (x) == MULT)
284 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
285 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
287 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
288 x = gen_rtx (GET_CODE (x), Pmode, op0, op1);
294 #ifdef POINTERS_EXTEND_UNSIGNED
296 /* Given X, a memory address in ptr_mode, convert it to an address
297 in Pmode, or vice versa (TO_MODE says which way). We take advantage of
298 the fact that pointers are not allowed to overflow by commuting arithmetic
299 operations over conversions so that address arithmetic insns can be
303 convert_memory_address (to_mode, x)
304 enum machine_mode to_mode;
309 switch (GET_CODE (x))
316 return gen_rtx (LABEL_REF, to_mode, XEXP (x, 0));
319 temp = gen_rtx (SYMBOL_REF, to_mode, XSTR (x, 0));
320 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x);
325 return gen_rtx (GET_CODE (x), to_mode,
326 convert_memory_address (to_mode, XEXP (x, 0)),
327 convert_memory_address (to_mode, XEXP (x, 1)));
330 return gen_rtx (CONST, to_mode,
331 convert_memory_address (to_mode, XEXP (x, 0)));
334 return convert_modes (to_mode,
335 to_mode == ptr_mode ? Pmode : ptr_mode,
336 x, POINTERS_EXTEND_UNSIGNED);
341 /* Given a memory address or facsimile X, construct a new address,
342 currently equivalent, that is stable: future stores won't change it.
344 X must be composed of constants, register and memory references
345 combined with addition, subtraction and multiplication:
346 in other words, just what you can get from expand_expr if sum_ok is 1.
348 Works by making copies of all regs and memory locations used
349 by X and combining them the same way X does.
350 You could also stabilize the reference to this address
351 by copying the address to a register with copy_to_reg;
352 but then you wouldn't get indexed addressing in the reference. */
358 if (GET_CODE (x) == REG)
360 if (REGNO (x) != FRAME_POINTER_REGNUM
361 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
362 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
367 else if (GET_CODE (x) == MEM)
369 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
370 || GET_CODE (x) == MULT)
372 register rtx op0 = copy_all_regs (XEXP (x, 0));
373 register rtx op1 = copy_all_regs (XEXP (x, 1));
374 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
375 x = gen_rtx (GET_CODE (x), Pmode, op0, op1);
380 /* Return something equivalent to X but valid as a memory address
381 for something of mode MODE. When X is not itself valid, this
382 works by copying X or subexpressions of it into registers. */
385 memory_address (mode, x)
386 enum machine_mode mode;
389 register rtx oldx = x;
391 #ifdef POINTERS_EXTEND_UNSIGNED
392 if (GET_MODE (x) == ptr_mode)
393 x = convert_memory_address (Pmode, x);
396 /* By passing constant addresses thru registers
397 we get a chance to cse them. */
398 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
399 x = force_reg (Pmode, x);
401 /* Accept a QUEUED that refers to a REG
402 even though that isn't a valid address.
403 On attempting to put this in an insn we will call protect_from_queue
404 which will turn it into a REG, which is valid. */
405 else if (GET_CODE (x) == QUEUED
406 && GET_CODE (QUEUED_VAR (x)) == REG)
409 /* We get better cse by rejecting indirect addressing at this stage.
410 Let the combiner create indirect addresses where appropriate.
411 For now, generate the code so that the subexpressions useful to share
412 are visible. But not if cse won't be done! */
415 if (! cse_not_expected && GET_CODE (x) != REG)
416 x = break_out_memory_refs (x);
418 /* At this point, any valid address is accepted. */
419 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
421 /* If it was valid before but breaking out memory refs invalidated it,
422 use it the old way. */
423 if (memory_address_p (mode, oldx))
426 /* Perform machine-dependent transformations on X
427 in certain cases. This is not necessary since the code
428 below can handle all possible cases, but machine-dependent
429 transformations can make better code. */
430 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
432 /* PLUS and MULT can appear in special ways
433 as the result of attempts to make an address usable for indexing.
434 Usually they are dealt with by calling force_operand, below.
435 But a sum containing constant terms is special
436 if removing them makes the sum a valid address:
437 then we generate that address in a register
438 and index off of it. We do this because it often makes
439 shorter code, and because the addresses thus generated
440 in registers often become common subexpressions. */
441 if (GET_CODE (x) == PLUS)
443 rtx constant_term = const0_rtx;
444 rtx y = eliminate_constant_term (x, &constant_term);
445 if (constant_term == const0_rtx
446 || ! memory_address_p (mode, y))
447 x = force_operand (x, NULL_RTX);
450 y = gen_rtx (PLUS, GET_MODE (x), copy_to_reg (y), constant_term);
451 if (! memory_address_p (mode, y))
452 x = force_operand (x, NULL_RTX);
458 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
459 x = force_operand (x, NULL_RTX);
461 /* If we have a register that's an invalid address,
462 it must be a hard reg of the wrong class. Copy it to a pseudo. */
463 else if (GET_CODE (x) == REG)
466 /* Last resort: copy the value to a register, since
467 the register is a valid address. */
469 x = force_reg (Pmode, x);
476 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
477 /* Don't copy an addr via a reg if it is one of our stack slots. */
478 && ! (GET_CODE (x) == PLUS
479 && (XEXP (x, 0) == virtual_stack_vars_rtx
480 || XEXP (x, 0) == virtual_incoming_args_rtx)))
482 if (general_operand (x, Pmode))
483 x = force_reg (Pmode, x);
485 x = force_operand (x, NULL_RTX);
491 /* If we didn't change the address, we are done. Otherwise, mark
492 a reg as a pointer if we have REG or REG + CONST_INT. */
495 else if (GET_CODE (x) == REG)
496 mark_reg_pointer (x);
497 else if (GET_CODE (x) == PLUS
498 && GET_CODE (XEXP (x, 0)) == REG
499 && GET_CODE (XEXP (x, 1)) == CONST_INT)
500 mark_reg_pointer (XEXP (x, 0));
502 /* OLDX may have been the address on a temporary. Update the address
503 to indicate that X is now used. */
504 update_temp_slot_address (oldx, x);
509 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
512 memory_address_noforce (mode, x)
513 enum machine_mode mode;
516 int ambient_force_addr = flag_force_addr;
520 val = memory_address (mode, x);
521 flag_force_addr = ambient_force_addr;
525 /* Convert a mem ref into one with a valid memory address.
526 Pass through anything else unchanged. */
532 if (GET_CODE (ref) != MEM)
534 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
536 /* Don't alter REF itself, since that is probably a stack slot. */
537 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
540 /* Return a modified copy of X with its memory address copied
541 into a temporary register to protect it from side effects.
542 If X is not a MEM, it is returned unchanged (and not copied).
543 Perhaps even if it is a MEM, if there is no need to change it. */
550 if (GET_CODE (x) != MEM)
553 if (rtx_unstable_p (addr))
555 rtx temp = copy_all_regs (addr);
557 if (GET_CODE (temp) != REG)
558 temp = copy_to_reg (temp);
559 mem = gen_rtx (MEM, GET_MODE (x), temp);
561 /* Mark returned memref with in_struct if it's in an array or
562 structure. Copy const and volatile from original memref. */
564 MEM_IN_STRUCT_P (mem) = MEM_IN_STRUCT_P (x) || GET_CODE (addr) == PLUS;
565 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
566 MEM_VOLATILE_P (mem) = MEM_VOLATILE_P (x);
572 /* Copy the value or contents of X to a new temp reg and return that reg. */
578 register rtx temp = gen_reg_rtx (GET_MODE (x));
580 /* If not an operand, must be an address with PLUS and MULT so
581 do the computation. */
582 if (! general_operand (x, VOIDmode))
583 x = force_operand (x, temp);
586 emit_move_insn (temp, x);
591 /* Like copy_to_reg but always give the new register mode Pmode
592 in case X is a constant. */
598 return copy_to_mode_reg (Pmode, x);
601 /* Like copy_to_reg but always give the new register mode MODE
602 in case X is a constant. */
605 copy_to_mode_reg (mode, x)
606 enum machine_mode mode;
609 register rtx temp = gen_reg_rtx (mode);
611 /* If not an operand, must be an address with PLUS and MULT so
612 do the computation. */
613 if (! general_operand (x, VOIDmode))
614 x = force_operand (x, temp);
616 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
619 emit_move_insn (temp, x);
623 /* Load X into a register if it is not already one.
624 Use mode MODE for the register.
625 X should be valid for mode MODE, but it may be a constant which
626 is valid for all integer modes; that's why caller must specify MODE.
628 The caller must not alter the value in the register we return,
629 since we mark it as a "constant" register. */
633 enum machine_mode mode;
636 register rtx temp, insn, set;
638 if (GET_CODE (x) == REG)
640 temp = gen_reg_rtx (mode);
641 insn = emit_move_insn (temp, x);
643 /* Let optimizers know that TEMP's value never changes
644 and that X can be substituted for it. Don't get confused
645 if INSN set something else (such as a SUBREG of TEMP). */
647 && (set = single_set (insn)) != 0
648 && SET_DEST (set) == temp)
650 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
655 REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_EQUAL, x, REG_NOTES (insn));
660 /* If X is a memory ref, copy its contents to a new temp reg and return
661 that reg. Otherwise, return X. */
668 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
670 temp = gen_reg_rtx (GET_MODE (x));
671 emit_move_insn (temp, x);
675 /* Copy X to TARGET (if it's nonzero and a reg)
676 or to a new temp reg and return that reg.
677 MODE is the mode to use for X in case it is a constant. */
680 copy_to_suggested_reg (x, target, mode)
682 enum machine_mode mode;
686 if (target && GET_CODE (target) == REG)
689 temp = gen_reg_rtx (mode);
691 emit_move_insn (temp, x);
695 /* Return the mode to use to store a scalar of TYPE and MODE.
696 PUNSIGNEDP points to the signedness of the type and may be adjusted
697 to show what signedness to use on extension operations.
699 FOR_CALL is non-zero if this call is promoting args for a call. */
702 promote_mode (type, mode, punsignedp, for_call)
704 enum machine_mode mode;
708 enum tree_code code = TREE_CODE (type);
709 int unsignedp = *punsignedp;
711 #ifdef PROMOTE_FOR_CALL_ONLY
719 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
720 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE:
721 PROMOTE_MODE (mode, unsignedp, type);
725 #ifdef POINTERS_EXTEND_UNSIGNED
728 unsignedp = POINTERS_EXTEND_UNSIGNED;
733 *punsignedp = unsignedp;
737 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
738 This pops when ADJUST is positive. ADJUST need not be constant. */
741 adjust_stack (adjust)
745 adjust = protect_from_queue (adjust, 0);
747 if (adjust == const0_rtx)
750 temp = expand_binop (Pmode,
751 #ifdef STACK_GROWS_DOWNWARD
756 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
759 if (temp != stack_pointer_rtx)
760 emit_move_insn (stack_pointer_rtx, temp);
763 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
764 This pushes when ADJUST is positive. ADJUST need not be constant. */
767 anti_adjust_stack (adjust)
771 adjust = protect_from_queue (adjust, 0);
773 if (adjust == const0_rtx)
776 temp = expand_binop (Pmode,
777 #ifdef STACK_GROWS_DOWNWARD
782 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
785 if (temp != stack_pointer_rtx)
786 emit_move_insn (stack_pointer_rtx, temp);
789 /* Round the size of a block to be pushed up to the boundary required
790 by this machine. SIZE is the desired size, which need not be constant. */
796 #ifdef STACK_BOUNDARY
797 int align = STACK_BOUNDARY / BITS_PER_UNIT;
800 if (GET_CODE (size) == CONST_INT)
802 int new = (INTVAL (size) + align - 1) / align * align;
803 if (INTVAL (size) != new)
804 size = GEN_INT (new);
808 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
809 but we know it can't. So add ourselves and then do TRUNC_DIV_EXPR. */
810 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
811 NULL_RTX, 1, OPTAB_LIB_WIDEN);
812 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
814 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
816 #endif /* STACK_BOUNDARY */
820 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
821 to a previously-created save area. If no save area has been allocated,
822 this function will allocate one. If a save area is specified, it
823 must be of the proper mode.
825 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
826 are emitted at the current position. */
829 emit_stack_save (save_level, psave, after)
830 enum save_level save_level;
835 /* The default is that we use a move insn and save in a Pmode object. */
836 rtx (*fcn) () = gen_move_insn;
837 enum machine_mode mode = Pmode;
839 /* See if this machine has anything special to do for this kind of save. */
842 #ifdef HAVE_save_stack_block
844 if (HAVE_save_stack_block)
846 fcn = gen_save_stack_block;
847 mode = insn_operand_mode[CODE_FOR_save_stack_block][0];
851 #ifdef HAVE_save_stack_function
853 if (HAVE_save_stack_function)
855 fcn = gen_save_stack_function;
856 mode = insn_operand_mode[CODE_FOR_save_stack_function][0];
860 #ifdef HAVE_save_stack_nonlocal
862 if (HAVE_save_stack_nonlocal)
864 fcn = gen_save_stack_nonlocal;
865 mode = insn_operand_mode[(int) CODE_FOR_save_stack_nonlocal][0];
871 /* If there is no save area and we have to allocate one, do so. Otherwise
872 verify the save area is the proper mode. */
876 if (mode != VOIDmode)
878 if (save_level == SAVE_NONLOCAL)
879 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
881 *psave = sa = gen_reg_rtx (mode);
886 if (mode == VOIDmode || GET_MODE (sa) != mode)
895 /* We must validize inside the sequence, to ensure that any instructions
896 created by the validize call also get moved to the right place. */
898 sa = validize_mem (sa);
899 emit_insn (fcn (sa, stack_pointer_rtx));
900 seq = gen_sequence ();
902 emit_insn_after (seq, after);
907 sa = validize_mem (sa);
908 emit_insn (fcn (sa, stack_pointer_rtx));
912 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
913 area made by emit_stack_save. If it is zero, we have nothing to do.
915 Put any emitted insns after insn AFTER, if nonzero, otherwise at
919 emit_stack_restore (save_level, sa, after)
920 enum save_level save_level;
924 /* The default is that we use a move insn. */
925 rtx (*fcn) () = gen_move_insn;
927 /* See if this machine has anything special to do for this kind of save. */
930 #ifdef HAVE_restore_stack_block
932 if (HAVE_restore_stack_block)
933 fcn = gen_restore_stack_block;
936 #ifdef HAVE_restore_stack_function
938 if (HAVE_restore_stack_function)
939 fcn = gen_restore_stack_function;
942 #ifdef HAVE_restore_stack_nonlocal
945 if (HAVE_restore_stack_nonlocal)
946 fcn = gen_restore_stack_nonlocal;
952 sa = validize_mem (sa);
959 emit_insn (fcn (stack_pointer_rtx, sa));
960 seq = gen_sequence ();
962 emit_insn_after (seq, after);
965 emit_insn (fcn (stack_pointer_rtx, sa));
968 /* Return an rtx representing the address of an area of memory dynamically
969 pushed on the stack. This region of memory is always aligned to
970 a multiple of BIGGEST_ALIGNMENT.
972 Any required stack pointer alignment is preserved.
974 SIZE is an rtx representing the size of the area.
975 TARGET is a place in which the address can be placed.
977 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
980 allocate_dynamic_stack_space (size, target, known_align)
985 /* If we're asking for zero bytes, it doesn't matter what we point
986 to since we can't dereference it. But return a reasonable
988 if (size == const0_rtx)
989 return virtual_stack_dynamic_rtx;
991 /* Otherwise, show we're calling alloca or equivalent. */
992 current_function_calls_alloca = 1;
994 /* Ensure the size is in the proper mode. */
995 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
996 size = convert_to_mode (Pmode, size, 1);
998 /* We will need to ensure that the address we return is aligned to
999 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
1000 always know its final value at this point in the compilation (it
1001 might depend on the size of the outgoing parameter lists, for
1002 example), so we must align the value to be returned in that case.
1003 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
1004 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
1005 We must also do an alignment operation on the returned value if
1006 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
1008 If we have to align, we must leave space in SIZE for the hole
1009 that might result from the alignment operation. */
1011 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || defined (ALLOCATE_OUTGOING_ARGS) || ! defined (STACK_BOUNDARY)
1012 #define MUST_ALIGN 1
1014 #define MUST_ALIGN (STACK_BOUNDARY < BIGGEST_ALIGNMENT)
1019 if (GET_CODE (size) == CONST_INT)
1020 size = GEN_INT (INTVAL (size)
1021 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
1023 size = expand_binop (Pmode, add_optab, size,
1024 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1025 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1028 #ifdef SETJMP_VIA_SAVE_AREA
1029 /* If setjmp restores regs from a save area in the stack frame,
1030 avoid clobbering the reg save area. Note that the offset of
1031 virtual_incoming_args_rtx includes the preallocated stack args space.
1032 It would be no problem to clobber that, but it's on the wrong side
1033 of the old save area. */
1036 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
1037 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
1038 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
1039 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1041 #endif /* SETJMP_VIA_SAVE_AREA */
1043 /* Round the size to a multiple of the required stack alignment.
1044 Since the stack if presumed to be rounded before this allocation,
1045 this will maintain the required alignment.
1047 If the stack grows downward, we could save an insn by subtracting
1048 SIZE from the stack pointer and then aligning the stack pointer.
1049 The problem with this is that the stack pointer may be unaligned
1050 between the execution of the subtraction and alignment insns and
1051 some machines do not allow this. Even on those that do, some
1052 signal handlers malfunction if a signal should occur between those
1053 insns. Since this is an extremely rare event, we have no reliable
1054 way of knowing which systems have this problem. So we avoid even
1055 momentarily mis-aligning the stack. */
1057 #ifdef STACK_BOUNDARY
1058 /* If we added a variable amount to SIZE,
1059 we can no longer assume it is aligned. */
1060 #if !defined (SETJMP_VIA_SAVE_AREA)
1061 if (MUST_ALIGN || known_align % STACK_BOUNDARY != 0)
1063 size = round_push (size);
1066 do_pending_stack_adjust ();
1068 /* Don't use a TARGET that isn't a pseudo. */
1069 if (target == 0 || GET_CODE (target) != REG
1070 || REGNO (target) < FIRST_PSEUDO_REGISTER)
1071 target = gen_reg_rtx (Pmode);
1073 mark_reg_pointer (target);
1075 #ifndef STACK_GROWS_DOWNWARD
1076 emit_move_insn (target, virtual_stack_dynamic_rtx);
1079 /* Perform the required allocation from the stack. Some systems do
1080 this differently than simply incrementing/decrementing from the
1082 #ifdef HAVE_allocate_stack
1083 if (HAVE_allocate_stack)
1085 enum machine_mode mode
1086 = insn_operand_mode[(int) CODE_FOR_allocate_stack][0];
1088 size = convert_modes (mode, ptr_mode, size, 1);
1090 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
1091 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
1093 size = copy_to_mode_reg (mode, size);
1095 emit_insn (gen_allocate_stack (size));
1100 size = convert_modes (Pmode, ptr_mode, size, 1);
1101 anti_adjust_stack (size);
1104 #ifdef STACK_GROWS_DOWNWARD
1105 emit_move_insn (target, virtual_stack_dynamic_rtx);
1110 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1111 but we know it can't. So add ourselves and then do TRUNC_DIV_EXPR. */
1112 target = expand_binop (Pmode, add_optab, target,
1113 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
1114 NULL_RTX, 1, OPTAB_LIB_WIDEN);
1115 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
1116 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1118 target = expand_mult (Pmode, target,
1119 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
1123 /* Some systems require a particular insn to refer to the stack
1124 to make the pages exist. */
1127 emit_insn (gen_probe ());
1130 /* Record the new stack level for nonlocal gotos. */
1131 if (nonlocal_goto_handler_slot != 0)
1132 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
1137 /* Return an rtx representing the register or memory location
1138 in which a scalar value of data type VALTYPE
1139 was returned by a function call to function FUNC.
1140 FUNC is a FUNCTION_DECL node if the precise function is known,
1144 hard_function_value (valtype, func)
1148 rtx val = FUNCTION_VALUE (valtype, func);
1149 if (GET_CODE (val) == REG
1150 && GET_MODE (val) == BLKmode)
1152 int bytes = int_size_in_bytes (valtype);
1153 enum machine_mode tmpmode;
1154 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
1155 tmpmode != MAX_MACHINE_MODE;
1156 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
1158 /* Have we found a large enough mode? */
1159 if (GET_MODE_SIZE (tmpmode) >= bytes)
1163 /* No suitable mode found. */
1164 if (tmpmode == MAX_MACHINE_MODE)
1167 PUT_MODE (val, tmpmode);
1172 /* Return an rtx representing the register or memory location
1173 in which a scalar value of mode MODE was returned by a library call. */
1176 hard_libcall_value (mode)
1177 enum machine_mode mode;
1179 return LIBCALL_VALUE (mode);
1182 /* Look up the tree code for a given rtx code
1183 to provide the arithmetic operation for REAL_ARITHMETIC.
1184 The function returns an int because the caller may not know
1185 what `enum tree_code' means. */
1188 rtx_to_tree_code (code)
1191 enum tree_code tcode;
1214 tcode = LAST_AND_UNUSED_TREE_CODE;
1217 return ((int) tcode);