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| Current File : //compat/linux/proc/68247/cwd/usr/src/contrib/gcc/loop-init.c |
/* Loop optimizer initialization routines and RTL loop optimization passes.
Copyright (C) 2002, 2003, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "obstack.h"
#include "basic-block.h"
#include "cfgloop.h"
#include "cfglayout.h"
#include "tree-pass.h"
#include "timevar.h"
#include "flags.h"
/* Initialize loop optimizer. This is used by the tree and RTL loop
optimizers. FLAGS specify what properties to compute and/or ensure for
loops. */
struct loops *
loop_optimizer_init (unsigned flags)
{
struct loops *loops = XCNEW (struct loops);
edge e;
edge_iterator ei;
static bool first_time = true;
if (first_time)
{
first_time = false;
init_set_costs ();
}
/* Avoid annoying special cases of edges going to exit
block. */
for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
if ((e->flags & EDGE_FALLTHRU) && !single_succ_p (e->src))
split_edge (e);
else
ei_next (&ei);
/* Find the loops. */
if (flow_loops_find (loops) <= 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;
/* Create pre-headers. */
if (flags & LOOPS_HAVE_PREHEADERS)
create_preheaders (loops, CP_SIMPLE_PREHEADERS);
/* Force all latches to have only single successor. */
if (flags & LOOPS_HAVE_SIMPLE_LATCHES)
force_single_succ_latches (loops);
/* Mark irreducible loops. */
if (flags & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
mark_irreducible_loops (loops);
if (flags & LOOPS_HAVE_MARKED_SINGLE_EXITS)
mark_single_exit_loops (loops);
/* Dump loops. */
flow_loops_dump (loops, dump_file, NULL, 1);
#ifdef ENABLE_CHECKING
verify_dominators (CDI_DOMINATORS);
verify_loop_structure (loops);
#endif
return loops;
}
/* Finalize loop optimizer. */
void
loop_optimizer_finalize (struct loops *loops)
{
unsigned i;
if (!loops)
return;
for (i = 1; i < loops->num; i++)
if (loops->parray[i])
free_simple_loop_desc (loops->parray[i]);
/* Clean up. */
flow_loops_free (loops);
free (loops);
/* Checking. */
#ifdef ENABLE_CHECKING
verify_flow_info ();
#endif
}
/* Gate for the RTL loop superpass. The actual passes are subpasses.
See passes.c for more on that. */
static bool
gate_handle_loop2 (void)
{
return (optimize > 0
&& (flag_move_loop_invariants
|| flag_unswitch_loops
|| flag_peel_loops
|| flag_unroll_loops
#ifdef HAVE_doloop_end
|| (flag_branch_on_count_reg && HAVE_doloop_end)
#endif
));
}
struct tree_opt_pass pass_loop2 =
{
"loop2", /* name */
gate_handle_loop2, /* gate */
NULL, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func |
TODO_ggc_collect, /* todo_flags_finish */
'L' /* letter */
};
/* Initialization of the RTL loop passes. */
static unsigned int
rtl_loop_init (void)
{
if (dump_file)
dump_flow_info (dump_file, dump_flags);
/* Initialize structures for layout changes. */
cfg_layout_initialize (0);
current_loops = loop_optimizer_init (LOOPS_NORMAL);
return 0;
}
struct tree_opt_pass pass_rtl_loop_init =
{
"loop2_init", /* name */
NULL, /* gate */
rtl_loop_init, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};
/* Finalization of the RTL loop passes. */
static unsigned int
rtl_loop_done (void)
{
basic_block bb;
if (current_loops)
loop_optimizer_finalize (current_loops);
free_dominance_info (CDI_DOMINATORS);
/* Finalize layout changes. */
FOR_EACH_BB (bb)
if (bb->next_bb != EXIT_BLOCK_PTR)
bb->aux = bb->next_bb;
cfg_layout_finalize ();
cleanup_cfg (CLEANUP_EXPENSIVE);
delete_trivially_dead_insns (get_insns (), max_reg_num ());
reg_scan (get_insns (), max_reg_num ());
if (dump_file)
dump_flow_info (dump_file, dump_flags);
current_loops = NULL;
return 0;
}
struct tree_opt_pass pass_rtl_loop_done =
{
"loop2_done", /* name */
NULL, /* gate */
rtl_loop_done, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};
/* Loop invariant code motion. */
static bool
gate_rtl_move_loop_invariants (void)
{
return flag_move_loop_invariants;
}
static unsigned int
rtl_move_loop_invariants (void)
{
if (current_loops)
move_loop_invariants (current_loops);
return 0;
}
struct tree_opt_pass pass_rtl_move_loop_invariants =
{
"loop2_invariant", /* name */
gate_rtl_move_loop_invariants, /* gate */
rtl_move_loop_invariants, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};
/* Loop unswitching for RTL. */
static bool
gate_rtl_unswitch (void)
{
return flag_unswitch_loops;
}
static unsigned int
rtl_unswitch (void)
{
if (current_loops)
unswitch_loops (current_loops);
return 0;
}
struct tree_opt_pass pass_rtl_unswitch =
{
"loop2_unswitch", /* name */
gate_rtl_unswitch, /* gate */
rtl_unswitch, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};
/* Loop unswitching for RTL. */
static bool
gate_rtl_unroll_and_peel_loops (void)
{
return (flag_peel_loops || flag_unroll_loops || flag_unroll_all_loops);
}
static unsigned int
rtl_unroll_and_peel_loops (void)
{
if (current_loops)
{
int flags = 0;
if (flag_peel_loops)
flags |= UAP_PEEL;
if (flag_unroll_loops)
flags |= UAP_UNROLL;
if (flag_unroll_all_loops)
flags |= UAP_UNROLL_ALL;
unroll_and_peel_loops (current_loops, flags);
}
return 0;
}
struct tree_opt_pass pass_rtl_unroll_and_peel_loops =
{
"loop2_unroll", /* name */
gate_rtl_unroll_and_peel_loops, /* gate */
rtl_unroll_and_peel_loops, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};
/* The doloop optimization. */
static bool
gate_rtl_doloop (void)
{
#ifdef HAVE_doloop_end
return (flag_branch_on_count_reg && HAVE_doloop_end);
#else
return 0;
#endif
}
static unsigned int
rtl_doloop (void)
{
#ifdef HAVE_doloop_end
if (current_loops)
doloop_optimize_loops (current_loops);
#endif
return 0;
}
struct tree_opt_pass pass_rtl_doloop =
{
"loop2_doloop", /* name */
gate_rtl_doloop, /* gate */
rtl_doloop, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_LOOP, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
'L' /* letter */
};