* arm.mc (return_address_mask): Use CC_REGNUM for the condition code
[official-gcc.git] / gcc / loop-init.c
blob44b9d61d5b87f060d1b2f859c5ef8ee38fa3c4f4
1 /* Loop optimizer initialization routines.
2 Copyright (C) 2002, 2003 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
21 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "tm.h"
25 #include "rtl.h"
26 #include "hard-reg-set.h"
27 #include "basic-block.h"
28 #include "cfgloop.h"
29 #include "cfglayout.h"
30 #include "gcov-io.h"
31 #include "profile.h"
33 /* Initialize loop optimizer. */
35 struct loops *
36 loop_optimizer_init (dumpfile)
37 FILE *dumpfile;
39 struct loops *loops = xcalloc (1, sizeof (struct loops));
40 edge e;
42 /* Avoid annoying special cases of edges going to exit
43 block. */
44 for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
45 if ((e->flags & EDGE_FALLTHRU) && e->src->succ->succ_next)
46 split_edge (e);
48 /* Find the loops. */
50 if (flow_loops_find (loops, LOOP_TREE) <= 1)
52 /* No loops. */
53 flow_loops_free (loops);
54 free (loops);
55 return NULL;
58 /* Not going to update these. */
59 free (loops->cfg.rc_order);
60 loops->cfg.rc_order = NULL;
61 free (loops->cfg.dfs_order);
62 loops->cfg.dfs_order = NULL;
64 /* Initialize structures for layout changes. */
65 cfg_layout_initialize (loops);
67 /* Create pre-headers. */
68 create_preheaders (loops, CP_SIMPLE_PREHEADERS | CP_INSIDE_CFGLAYOUT);
70 /* Force all latches to have only single successor. */
71 force_single_succ_latches (loops);
73 /* Mark irreducible loops. */
74 mark_irreducible_loops (loops);
76 /* Dump loops. */
77 flow_loops_dump (loops, dumpfile, NULL, 1);
79 #ifdef ENABLE_CHECKING
80 verify_dominators (loops->cfg.dom);
81 verify_loop_structure (loops);
82 #endif
84 return loops;
87 /* Finalize loop optimizer. */
88 void
89 loop_optimizer_finalize (loops, dumpfile)
90 struct loops *loops;
91 FILE *dumpfile;
93 basic_block bb;
95 /* Finalize layout changes. */
96 /* Make chain. */
97 FOR_EACH_BB (bb)
98 if (bb->next_bb != EXIT_BLOCK_PTR)
99 RBI (bb)->next = bb->next_bb;
101 /* Another dump. */
102 flow_loops_dump (loops, dumpfile, NULL, 1);
104 /* Clean up. */
105 flow_loops_free (loops);
106 free (loops);
108 /* Finalize changes. */
109 cfg_layout_finalize ();
111 /* Checking. */
112 #ifdef ENABLE_CHECKING
113 verify_flow_info ();
114 #endif