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+/* Loop optimizer initialization routines.
+ Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "cfgloop.h"
+#include "cfglayout.h"
+#include "gcov-io.h"
+#include "profile.h"
+
+/* Initialize loop optimizer. */
+
+struct loops *
+loop_optimizer_init (dumpfile)
+ FILE *dumpfile;
+{
+ struct loops *loops = xcalloc (1, sizeof (struct loops));
+ edge e;
+
+ /* Avoid annoying special cases of edges going to exit
+ block. */
+ for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
+ if ((e->flags & EDGE_FALLTHRU) && e->src->succ->succ_next)
+ split_edge (e);
+
+ /* Find the loops. */
+
+ if (flow_loops_find (loops, LOOP_TREE) <= 1)
+ {
+ /* No loops. */
+ flow_loops_free (loops);
+ free (loops);
+ return NULL;
+ }
+
+ /* Not going to update these. */
+ free (loops->cfg.rc_order);
+ loops->cfg.rc_order = NULL;
+ free (loops->cfg.dfs_order);
+ loops->cfg.dfs_order = NULL;
+
+ /* Initialize structures for layout changes. */
+ cfg_layout_initialize (loops);
+
+ /* Create pre-headers. */
+ create_preheaders (loops, CP_SIMPLE_PREHEADERS | CP_INSIDE_CFGLAYOUT);
+
+ /* Force all latches to have only single successor. */
+ force_single_succ_latches (loops);
+
+ /* Mark irreducible loops. */
+ mark_irreducible_loops (loops);
+
+ /* Dump loops. */
+ flow_loops_dump (loops, dumpfile, NULL, 1);
+
+#ifdef ENABLE_CHECKING
+ verify_dominators (loops->cfg.dom);
+ verify_loop_structure (loops);
+#endif
+
+ return loops;
+}
+
+/* Finalize loop optimizer. */
+void
+loop_optimizer_finalize (loops, dumpfile)
+ struct loops *loops;
+ FILE *dumpfile;
+{
+ basic_block bb;
+
+ /* Finalize layout changes. */
+ /* Make chain. */
+ FOR_EACH_BB (bb)
+ if (bb->next_bb != EXIT_BLOCK_PTR)
+ RBI (bb)->next = bb->next_bb;
+
+ /* Another dump. */
+ flow_loops_dump (loops, dumpfile, NULL, 1);
+
+ /* Clean up. */
+ flow_loops_free (loops);
+ free (loops);
+
+ /* Finalize changes. */
+ cfg_layout_finalize ();
+
+ /* Checking. */
+#ifdef ENABLE_CHECKING
+ verify_flow_info ();
+#endif
+}
+