Add an UNSPEC_PROLOGUE_USE to prevent the link register from being considered dead.
[official-gcc.git] / gcc / lists.c
blob78accceccd88d36af0c2e25074658373dda8a7dd
1 /* List management for the GNU C-Compiler expander.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "tm.h"
26 #include "toplev.h"
27 #include "rtl.h"
28 #include "ggc.h"
30 static void free_list PARAMS ((rtx *, rtx *));
32 /* Functions for maintaining cache-able lists of EXPR_LIST and INSN_LISTs. */
34 /* An INSN_LIST containing all INSN_LISTs allocated but currently unused. */
35 static GTY ((deletable (""))) rtx unused_insn_list;
37 /* An EXPR_LIST containing all EXPR_LISTs allocated but currently unused. */
38 static GTY ((deletable (""))) rtx unused_expr_list;
41 /* This function will free an entire list of either EXPR_LIST or INSN_LIST
42 nodes. This is to be used only on lists that consist exclusively of
43 nodes of one type only. This is only called by free_EXPR_LIST_list
44 and free_INSN_LIST_list. */
45 static void
46 free_list (listp, unused_listp)
47 rtx *listp, *unused_listp;
49 rtx link, prev_link;
51 prev_link = *listp;
52 link = XEXP (prev_link, 1);
54 while (link)
56 prev_link = link;
57 link = XEXP (link, 1);
60 XEXP (prev_link, 1) = *unused_listp;
61 *unused_listp = *listp;
62 *listp = 0;
65 /* This call is used in place of a gen_rtx_INSN_LIST. If there is a cached
66 node available, we'll use it, otherwise a call to gen_rtx_INSN_LIST
67 is made. */
68 rtx
69 alloc_INSN_LIST (val, next)
70 rtx val, next;
72 rtx r;
74 if (unused_insn_list)
76 r = unused_insn_list;
77 unused_insn_list = XEXP (r, 1);
78 XEXP (r, 0) = val;
79 XEXP (r, 1) = next;
80 PUT_REG_NOTE_KIND (r, VOIDmode);
82 else
83 r = gen_rtx_INSN_LIST (VOIDmode, val, next);
85 return r;
88 /* This call is used in place of a gen_rtx_EXPR_LIST. If there is a cached
89 node available, we'll use it, otherwise a call to gen_rtx_EXPR_LIST
90 is made. */
91 rtx
92 alloc_EXPR_LIST (kind, val, next)
93 int kind;
94 rtx val, next;
96 rtx r;
98 if (unused_expr_list)
100 r = unused_expr_list;
101 unused_expr_list = XEXP (r, 1);
102 XEXP (r, 0) = val;
103 XEXP (r, 1) = next;
104 PUT_REG_NOTE_KIND (r, kind);
106 else
107 r = gen_rtx_EXPR_LIST (kind, val, next);
109 return r;
112 /* This function will free up an entire list of EXPR_LIST nodes. */
113 void
114 free_EXPR_LIST_list (listp)
115 rtx *listp;
117 if (*listp == 0)
118 return;
119 free_list (listp, &unused_expr_list);
122 /* This function will free up an entire list of INSN_LIST nodes. */
123 void
124 free_INSN_LIST_list (listp)
125 rtx *listp;
127 if (*listp == 0)
128 return;
129 free_list (listp, &unused_insn_list);
132 /* This function will free up an individual EXPR_LIST node. */
133 void
134 free_EXPR_LIST_node (ptr)
135 rtx ptr;
137 XEXP (ptr, 1) = unused_expr_list;
138 unused_expr_list = ptr;
141 /* This function will free up an individual INSN_LIST node. */
142 void
143 free_INSN_LIST_node (ptr)
144 rtx ptr;
146 XEXP (ptr, 1) = unused_insn_list;
147 unused_insn_list = ptr;
150 #include "gt-lists.h"