1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987, 1991 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
26 #include "hard-reg-set.h"
27 #include "insn-config.h"
29 #include "insn-flags.h"
30 #include "insn-codes.h"
32 /* Return an rtx for the sum of X and the integer C.
34 This function should be used via the `plus_constant' macro. */
37 plus_constant_wide (x, c)
39 register HOST_WIDE_INT c;
41 register RTX_CODE code;
42 register enum machine_mode mode;
56 return GEN_INT (INTVAL (x) + c);
60 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x);
61 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x);
63 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0;
66 add_double (l1, h1, l2, h2, &lv, &hv);
68 return immed_double_const (lv, hv, VOIDmode);
72 /* If this is a reference to the constant pool, try replacing it with
73 a reference to a new constant. If the resulting address isn't
74 valid, don't return it because we have no way to validize it. */
75 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
76 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
79 = force_const_mem (GET_MODE (x),
80 plus_constant (get_pool_constant (XEXP (x, 0)),
82 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
88 /* If adding to something entirely constant, set a flag
89 so that we can add a CONST around the result. */
100 /* The interesting case is adding the integer to a sum.
101 Look for constant term in the sum and combine
102 with C. For an integer constant term, we make a combined
103 integer. For a constant term that is not an explicit integer,
104 we cannot really combine, but group them together anyway.
106 Use a recursive call in case the remaining operand is something
107 that we handle specially, such as a SYMBOL_REF. */
109 if (GET_CODE (XEXP (x, 1)) == CONST_INT)
110 return plus_constant (XEXP (x, 0), c + INTVAL (XEXP (x, 1)));
111 else if (CONSTANT_P (XEXP (x, 0)))
112 return gen_rtx (PLUS, mode,
113 plus_constant (XEXP (x, 0), c),
115 else if (CONSTANT_P (XEXP (x, 1)))
116 return gen_rtx (PLUS, mode,
118 plus_constant (XEXP (x, 1), c));
122 x = gen_rtx (PLUS, mode, x, GEN_INT (c));
124 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
126 else if (all_constant)
127 return gen_rtx (CONST, mode, x);
132 /* This is the same as `plus_constant', except that it handles LO_SUM.
134 This function should be used via the `plus_constant_for_output' macro. */
137 plus_constant_for_output_wide (x, c)
139 register HOST_WIDE_INT c;
141 register RTX_CODE code = GET_CODE (x);
142 register enum machine_mode mode = GET_MODE (x);
143 int all_constant = 0;
145 if (GET_CODE (x) == LO_SUM)
146 return gen_rtx (LO_SUM, mode, XEXP (x, 0),
147 plus_constant_for_output (XEXP (x, 1), c));
150 return plus_constant (x, c);
153 /* If X is a sum, return a new sum like X but lacking any constant terms.
154 Add all the removed constant terms into *CONSTPTR.
155 X itself is not altered. The result != X if and only if
156 it is not isomorphic to X. */
159 eliminate_constant_term (x, constptr)
166 if (GET_CODE (x) != PLUS)
169 /* First handle constants appearing at this level explicitly. */
170 if (GET_CODE (XEXP (x, 1)) == CONST_INT
171 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
173 && GET_CODE (tem) == CONST_INT)
176 return eliminate_constant_term (XEXP (x, 0), constptr);
180 x0 = eliminate_constant_term (XEXP (x, 0), &tem);
181 x1 = eliminate_constant_term (XEXP (x, 1), &tem);
182 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
183 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x),
185 && GET_CODE (tem) == CONST_INT)
188 return gen_rtx (PLUS, GET_MODE (x), x0, x1);
194 /* Returns the insn that next references REG after INSN, or 0
195 if REG is clobbered before next referenced or we cannot find
196 an insn that references REG in a straight-line piece of code. */
199 find_next_ref (reg, insn)
205 for (insn = NEXT_INSN (insn); insn; insn = next)
207 next = NEXT_INSN (insn);
208 if (GET_CODE (insn) == NOTE)
210 if (GET_CODE (insn) == CODE_LABEL
211 || GET_CODE (insn) == BARRIER)
213 if (GET_CODE (insn) == INSN
214 || GET_CODE (insn) == JUMP_INSN
215 || GET_CODE (insn) == CALL_INSN)
217 if (reg_set_p (reg, insn))
219 if (reg_mentioned_p (reg, PATTERN (insn)))
221 if (GET_CODE (insn) == JUMP_INSN)
223 if (simplejump_p (insn))
224 next = JUMP_LABEL (insn);
228 if (GET_CODE (insn) == CALL_INSN
229 && REGNO (reg) < FIRST_PSEUDO_REGISTER
230 && call_used_regs[REGNO (reg)])
239 /* Return an rtx for the size in bytes of the value of EXP. */
245 return expand_expr (size_in_bytes (TREE_TYPE (exp)),
246 NULL_RTX, TYPE_MODE (sizetype), 0);
249 /* Return a copy of X in which all memory references
250 and all constants that involve symbol refs
251 have been replaced with new temporary registers.
252 Also emit code to load the memory locations and constants
253 into those registers.
255 If X contains no such constants or memory references,
256 X itself (not a copy) is returned.
258 If a constant is found in the address that is not a legitimate constant
259 in an insn, it is left alone in the hope that it might be valid in the
262 X may contain no arithmetic except addition, subtraction and multiplication.
263 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
266 break_out_memory_refs (x)
269 if (GET_CODE (x) == MEM
270 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
271 && GET_MODE (x) != VOIDmode))
273 register rtx temp = force_reg (GET_MODE (x), x);
274 mark_reg_pointer (temp);
277 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
278 || GET_CODE (x) == MULT)
280 register rtx op0 = break_out_memory_refs (XEXP (x, 0));
281 register rtx op1 = break_out_memory_refs (XEXP (x, 1));
282 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
283 x = gen_rtx (GET_CODE (x), Pmode, op0, op1);
288 /* Given a memory address or facsimile X, construct a new address,
289 currently equivalent, that is stable: future stores won't change it.
291 X must be composed of constants, register and memory references
292 combined with addition, subtraction and multiplication:
293 in other words, just what you can get from expand_expr if sum_ok is 1.
295 Works by making copies of all regs and memory locations used
296 by X and combining them the same way X does.
297 You could also stabilize the reference to this address
298 by copying the address to a register with copy_to_reg;
299 but then you wouldn't get indexed addressing in the reference. */
305 if (GET_CODE (x) == REG)
307 if (REGNO (x) != FRAME_POINTER_REGNUM
308 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
309 && REGNO (x) != HARD_FRAME_POINTER_REGNUM
314 else if (GET_CODE (x) == MEM)
316 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
317 || GET_CODE (x) == MULT)
319 register rtx op0 = copy_all_regs (XEXP (x, 0));
320 register rtx op1 = copy_all_regs (XEXP (x, 1));
321 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
322 x = gen_rtx (GET_CODE (x), Pmode, op0, op1);
327 /* Return something equivalent to X but valid as a memory address
328 for something of mode MODE. When X is not itself valid, this
329 works by copying X or subexpressions of it into registers. */
332 memory_address (mode, x)
333 enum machine_mode mode;
338 /* By passing constant addresses thru registers
339 we get a chance to cse them. */
340 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
341 return force_reg (Pmode, x);
343 /* Accept a QUEUED that refers to a REG
344 even though that isn't a valid address.
345 On attempting to put this in an insn we will call protect_from_queue
346 which will turn it into a REG, which is valid. */
347 if (GET_CODE (x) == QUEUED
348 && GET_CODE (QUEUED_VAR (x)) == REG)
351 /* We get better cse by rejecting indirect addressing at this stage.
352 Let the combiner create indirect addresses where appropriate.
353 For now, generate the code so that the subexpressions useful to share
354 are visible. But not if cse won't be done! */
356 if (! cse_not_expected && GET_CODE (x) != REG)
357 x = break_out_memory_refs (x);
359 /* At this point, any valid address is accepted. */
360 GO_IF_LEGITIMATE_ADDRESS (mode, x, win);
362 /* If it was valid before but breaking out memory refs invalidated it,
363 use it the old way. */
364 if (memory_address_p (mode, oldx))
367 /* Perform machine-dependent transformations on X
368 in certain cases. This is not necessary since the code
369 below can handle all possible cases, but machine-dependent
370 transformations can make better code. */
371 LEGITIMIZE_ADDRESS (x, oldx, mode, win);
373 /* PLUS and MULT can appear in special ways
374 as the result of attempts to make an address usable for indexing.
375 Usually they are dealt with by calling force_operand, below.
376 But a sum containing constant terms is special
377 if removing them makes the sum a valid address:
378 then we generate that address in a register
379 and index off of it. We do this because it often makes
380 shorter code, and because the addresses thus generated
381 in registers often become common subexpressions. */
382 if (GET_CODE (x) == PLUS)
384 rtx constant_term = const0_rtx;
385 rtx y = eliminate_constant_term (x, &constant_term);
386 if (constant_term == const0_rtx
387 || ! memory_address_p (mode, y))
388 return force_operand (x, NULL_RTX);
390 y = gen_rtx (PLUS, GET_MODE (x), copy_to_reg (y), constant_term);
391 if (! memory_address_p (mode, y))
392 return force_operand (x, NULL_RTX);
395 if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
396 return force_operand (x, NULL_RTX);
398 /* If we have a register that's an invalid address,
399 it must be a hard reg of the wrong class. Copy it to a pseudo. */
400 if (GET_CODE (x) == REG)
401 return copy_to_reg (x);
403 /* Last resort: copy the value to a register, since
404 the register is a valid address. */
405 return force_reg (Pmode, x);
410 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG
411 /* Don't copy an addr via a reg if it is one of our stack slots. */
412 && ! (GET_CODE (x) == PLUS
413 && (XEXP (x, 0) == virtual_stack_vars_rtx
414 || XEXP (x, 0) == virtual_incoming_args_rtx)))
416 if (general_operand (x, Pmode))
417 return force_reg (Pmode, x);
419 return force_operand (x, NULL_RTX);
424 /* Like `memory_address' but pretend `flag_force_addr' is 0. */
427 memory_address_noforce (mode, x)
428 enum machine_mode mode;
431 int ambient_force_addr = flag_force_addr;
435 val = memory_address (mode, x);
436 flag_force_addr = ambient_force_addr;
440 /* Convert a mem ref into one with a valid memory address.
441 Pass through anything else unchanged. */
447 if (GET_CODE (ref) != MEM)
449 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0)))
451 /* Don't alter REF itself, since that is probably a stack slot. */
452 return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
455 /* Return a modified copy of X with its memory address copied
456 into a temporary register to protect it from side effects.
457 If X is not a MEM, it is returned unchanged (and not copied).
458 Perhaps even if it is a MEM, if there is no need to change it. */
465 if (GET_CODE (x) != MEM)
468 if (rtx_unstable_p (addr))
470 rtx temp = copy_all_regs (addr);
472 if (GET_CODE (temp) != REG)
473 temp = copy_to_reg (temp);
474 mem = gen_rtx (MEM, GET_MODE (x), temp);
476 /* Mark returned memref with in_struct if it's in an array or
477 structure. Copy const and volatile from original memref. */
479 MEM_IN_STRUCT_P (mem) = MEM_IN_STRUCT_P (x) || GET_CODE (addr) == PLUS;
480 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x);
481 MEM_VOLATILE_P (mem) = MEM_VOLATILE_P (x);
487 /* Copy the value or contents of X to a new temp reg and return that reg. */
493 register rtx temp = gen_reg_rtx (GET_MODE (x));
495 /* If not an operand, must be an address with PLUS and MULT so
496 do the computation. */
497 if (! general_operand (x, VOIDmode))
498 x = force_operand (x, temp);
501 emit_move_insn (temp, x);
506 /* Like copy_to_reg but always give the new register mode Pmode
507 in case X is a constant. */
513 return copy_to_mode_reg (Pmode, x);
516 /* Like copy_to_reg but always give the new register mode MODE
517 in case X is a constant. */
520 copy_to_mode_reg (mode, x)
521 enum machine_mode mode;
524 register rtx temp = gen_reg_rtx (mode);
526 /* If not an operand, must be an address with PLUS and MULT so
527 do the computation. */
528 if (! general_operand (x, VOIDmode))
529 x = force_operand (x, temp);
531 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode)
534 emit_move_insn (temp, x);
538 /* Load X into a register if it is not already one.
539 Use mode MODE for the register.
540 X should be valid for mode MODE, but it may be a constant which
541 is valid for all integer modes; that's why caller must specify MODE.
543 The caller must not alter the value in the register we return,
544 since we mark it as a "constant" register. */
548 enum machine_mode mode;
551 register rtx temp, insn;
553 if (GET_CODE (x) == REG)
555 temp = gen_reg_rtx (mode);
556 insn = emit_move_insn (temp, x);
557 /* Let optimizers know that TEMP's value never changes
558 and that X can be substituted for it. */
561 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
566 REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_EQUAL, x, REG_NOTES (insn));
571 /* If X is a memory ref, copy its contents to a new temp reg and return
572 that reg. Otherwise, return X. */
579 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode)
581 temp = gen_reg_rtx (GET_MODE (x));
582 emit_move_insn (temp, x);
586 /* Copy X to TARGET (if it's nonzero and a reg)
587 or to a new temp reg and return that reg.
588 MODE is the mode to use for X in case it is a constant. */
591 copy_to_suggested_reg (x, target, mode)
593 enum machine_mode mode;
597 if (target && GET_CODE (target) == REG)
600 temp = gen_reg_rtx (mode);
602 emit_move_insn (temp, x);
606 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
607 This pops when ADJUST is positive. ADJUST need not be constant. */
610 adjust_stack (adjust)
614 adjust = protect_from_queue (adjust, 0);
616 if (adjust == const0_rtx)
619 temp = expand_binop (Pmode,
620 #ifdef STACK_GROWS_DOWNWARD
625 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
628 if (temp != stack_pointer_rtx)
629 emit_move_insn (stack_pointer_rtx, temp);
632 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
633 This pushes when ADJUST is positive. ADJUST need not be constant. */
636 anti_adjust_stack (adjust)
640 adjust = protect_from_queue (adjust, 0);
642 if (adjust == const0_rtx)
645 temp = expand_binop (Pmode,
646 #ifdef STACK_GROWS_DOWNWARD
651 stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
654 if (temp != stack_pointer_rtx)
655 emit_move_insn (stack_pointer_rtx, temp);
658 /* Round the size of a block to be pushed up to the boundary required
659 by this machine. SIZE is the desired size, which need not be constant. */
665 #ifdef STACK_BOUNDARY
666 int align = STACK_BOUNDARY / BITS_PER_UNIT;
669 if (GET_CODE (size) == CONST_INT)
671 int new = (INTVAL (size) + align - 1) / align * align;
672 if (INTVAL (size) != new)
673 size = GEN_INT (new);
677 size = expand_divmod (0, CEIL_DIV_EXPR, Pmode, size, GEN_INT (align),
679 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
681 #endif /* STACK_BOUNDARY */
685 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
686 to a previously-created save area. If no save area has been allocated,
687 this function will allocate one. If a save area is specified, it
688 must be of the proper mode.
690 The insns are emitted after insn AFTER, if nonzero, otherwise the insns
691 are emitted at the current position. */
694 emit_stack_save (save_level, psave, after)
695 enum save_level save_level;
700 /* The default is that we use a move insn and save in a Pmode object. */
701 rtx (*fcn) () = gen_move_insn;
702 enum machine_mode mode = Pmode;
704 /* See if this machine has anything special to do for this kind of save. */
707 #ifdef HAVE_save_stack_block
709 if (HAVE_save_stack_block)
711 fcn = gen_save_stack_block;
712 mode = insn_operand_mode[CODE_FOR_save_stack_block][0];
716 #ifdef HAVE_save_stack_function
718 if (HAVE_save_stack_function)
720 fcn = gen_save_stack_function;
721 mode = insn_operand_mode[CODE_FOR_save_stack_function][0];
725 #ifdef HAVE_save_stack_nonlocal
727 if (HAVE_save_stack_nonlocal)
729 fcn = gen_save_stack_nonlocal;
730 mode = insn_operand_mode[CODE_FOR_save_stack_nonlocal][0];
736 /* If there is no save area and we have to allocate one, do so. Otherwise
737 verify the save area is the proper mode. */
741 if (mode != VOIDmode)
743 if (save_level == SAVE_NONLOCAL)
744 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
746 *psave = sa = gen_reg_rtx (mode);
751 if (mode == VOIDmode || GET_MODE (sa) != mode)
760 /* We must validize inside the sequence, to ensure that any instructions
761 created by the validize call also get moved to the right place. */
763 sa = validize_mem (sa);
764 emit_insn (fcn (sa, stack_pointer_rtx));
765 seq = gen_sequence ();
767 emit_insn_after (seq, after);
772 sa = validize_mem (sa);
773 emit_insn (fcn (sa, stack_pointer_rtx));
777 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
778 area made by emit_stack_save. If it is zero, we have nothing to do.
780 Put any emitted insns after insn AFTER, if nonzero, otherwise at
784 emit_stack_restore (save_level, sa, after)
785 enum save_level save_level;
789 /* The default is that we use a move insn. */
790 rtx (*fcn) () = gen_move_insn;
792 /* See if this machine has anything special to do for this kind of save. */
795 #ifdef HAVE_restore_stack_block
797 if (HAVE_restore_stack_block)
798 fcn = gen_restore_stack_block;
801 #ifdef HAVE_restore_stack_function
803 if (HAVE_restore_stack_function)
804 fcn = gen_restore_stack_function;
807 #ifdef HAVE_restore_stack_nonlocal
810 if (HAVE_restore_stack_nonlocal)
811 fcn = gen_restore_stack_nonlocal;
817 sa = validize_mem (sa);
824 emit_insn (fcn (stack_pointer_rtx, sa));
825 seq = gen_sequence ();
827 emit_insn_after (seq, after);
830 emit_insn (fcn (stack_pointer_rtx, sa));
833 /* Return an rtx representing the address of an area of memory dynamically
834 pushed on the stack. This region of memory is always aligned to
835 a multiple of BIGGEST_ALIGNMENT.
837 Any required stack pointer alignment is preserved.
839 SIZE is an rtx representing the size of the area.
840 TARGET is a place in which the address can be placed.
842 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */
845 allocate_dynamic_stack_space (size, target, known_align)
850 /* Ensure the size is in the proper mode. */
851 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
852 size = convert_to_mode (Pmode, size, 1);
854 /* We will need to ensure that the address we return is aligned to
855 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't
856 always know its final value at this point in the compilation (it
857 might depend on the size of the outgoing parameter lists, for
858 example), so we must align the value to be returned in that case.
859 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if
860 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
861 We must also do an alignment operation on the returned value if
862 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
864 If we have to align, we must leave space in SIZE for the hole
865 that might result from the alignment operation. */
867 #if defined (STACK_DYNAMIC_OFFSET) || defined(STACK_POINTER_OFFSET) || defined (ALLOCATE_OUTGOING_ARGS)
871 #if ! defined (MUST_ALIGN) && (!defined(STACK_BOUNDARY) || STACK_BOUNDARY < BIGGEST_ALIGNMENT)
877 #if 0 /* It turns out we must always make extra space, if MUST_ALIGN
878 because we must always round the address up at the end,
879 because we don't know whether the dynamic offset
880 will mess up the desired alignment. */
881 /* If we have to round the address up regardless of known_align,
882 make extra space regardless, also. */
883 if (known_align % BIGGEST_ALIGNMENT != 0)
886 if (GET_CODE (size) == CONST_INT)
887 size = GEN_INT (INTVAL (size)
888 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1));
890 size = expand_binop (Pmode, add_optab, size,
891 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
892 NULL_RTX, 1, OPTAB_LIB_WIDEN);
897 #ifdef SETJMP_VIA_SAVE_AREA
898 /* If setjmp restores regs from a save area in the stack frame,
899 avoid clobbering the reg save area. Note that the offset of
900 virtual_incoming_args_rtx includes the preallocated stack args space.
901 It would be no problem to clobber that, but it's on the wrong side
902 of the old save area. */
905 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
906 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN);
907 size = expand_binop (Pmode, add_optab, size, dynamic_offset,
908 NULL_RTX, 1, OPTAB_LIB_WIDEN);
910 #endif /* SETJMP_VIA_SAVE_AREA */
912 /* Round the size to a multiple of the required stack alignment.
913 Since the stack if presumed to be rounded before this allocation,
914 this will maintain the required alignment.
916 If the stack grows downward, we could save an insn by subtracting
917 SIZE from the stack pointer and then aligning the stack pointer.
918 The problem with this is that the stack pointer may be unaligned
919 between the execution of the subtraction and alignment insns and
920 some machines do not allow this. Even on those that do, some
921 signal handlers malfunction if a signal should occur between those
922 insns. Since this is an extremely rare event, we have no reliable
923 way of knowing which systems have this problem. So we avoid even
924 momentarily mis-aligning the stack. */
926 #ifdef STACK_BOUNDARY
927 /* If we added a variable amount to SIZE,
928 we can no longer assume it is aligned. */
929 #if !defined (SETJMP_VIA_SAVE_AREA) && !defined (MUST_ALIGN)
930 if (known_align % STACK_BOUNDARY != 0)
932 size = round_push (size);
935 do_pending_stack_adjust ();
937 /* Don't use a TARGET that isn't a pseudo. */
938 if (target == 0 || GET_CODE (target) != REG
939 || REGNO (target) < FIRST_PSEUDO_REGISTER)
940 target = gen_reg_rtx (Pmode);
942 mark_reg_pointer (target);
944 #ifndef STACK_GROWS_DOWNWARD
945 emit_move_insn (target, virtual_stack_dynamic_rtx);
948 /* Perform the required allocation from the stack. Some systems do
949 this differently than simply incrementing/decrementing from the
951 #ifdef HAVE_allocate_stack
952 if (HAVE_allocate_stack)
954 enum machine_mode mode
955 = insn_operand_mode[(int) CODE_FOR_allocate_stack][0];
957 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]
958 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0])
960 size = copy_to_mode_reg (mode, size);
962 emit_insn (gen_allocate_stack (size));
966 anti_adjust_stack (size);
968 #ifdef STACK_GROWS_DOWNWARD
969 emit_move_insn (target, virtual_stack_dynamic_rtx);
973 #if 0 /* Even if we know the stack pointer has enough alignment,
974 there's no way to tell whether virtual_stack_dynamic_rtx shares that
975 alignment, so we still need to round the address up. */
976 if (known_align % BIGGEST_ALIGNMENT != 0)
979 target = expand_divmod (0, CEIL_DIV_EXPR, Pmode, target,
980 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
983 target = expand_mult (Pmode, target,
984 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
989 /* Some systems require a particular insn to refer to the stack
990 to make the pages exist. */
993 emit_insn (gen_probe ());
999 /* Return an rtx representing the register or memory location
1000 in which a scalar value of data type VALTYPE
1001 was returned by a function call to function FUNC.
1002 FUNC is a FUNCTION_DECL node if the precise function is known,
1006 hard_function_value (valtype, func)
1010 return FUNCTION_VALUE (valtype, func);
1013 /* Return an rtx representing the register or memory location
1014 in which a scalar value of mode MODE was returned by a library call. */
1017 hard_libcall_value (mode)
1018 enum machine_mode mode;
1020 return LIBCALL_VALUE (mode);
1023 /* Look up the tree code for a given rtx code
1024 to provide the arithmetic operation for REAL_ARITHMETIC.
1025 The function returns an int because the caller may not know
1026 what `enum tree_code' means. */
1029 rtx_to_tree_code (code)
1032 enum tree_code tcode;
1055 tcode = LAST_AND_UNUSED_TREE_CODE;
1058 return ((int) tcode);