/* Loop unswitching for GNU compiler.
- Copyright (C) 2002 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2003 Free Software Foundation, Inc.
This file is part of GCC.
containing subloops would not be very large compared to complications
with handling this case. */
-static struct loop *unswitch_loop PARAMS ((struct loops *,
- struct loop *, basic_block));
-static void unswitch_single_loop PARAMS ((struct loops *, struct loop *,
- rtx, int));
-static bool may_unswitch_on_p PARAMS ((struct loops *, basic_block,
- struct loop *, basic_block *));
-static rtx reversed_condition PARAMS ((rtx));
+static struct loop *unswitch_loop (struct loops *, struct loop *,
+ basic_block);
+static void unswitch_single_loop (struct loops *, struct loop *, rtx, int);
+static bool may_unswitch_on_p (struct loops *, basic_block, struct loop *,
+ basic_block *);
+static rtx reversed_condition (rtx);
/* Main entry point. Perform loop unswitching on all suitable LOOPS. */
void
-unswitch_loops (loops)
- struct loops *loops;
+unswitch_loops (struct loops *loops)
{
int i, num;
struct loop *loop;
/* Go through inner loops (only original ones). */
num = loops->num;
-
+
for (i = 1; i < num; i++)
{
/* Removed loop? */
basic blocks (for what it means see comments below). List of basic blocks
inside LOOP is provided in BODY to save time. */
static bool
-may_unswitch_on_p (loops, bb, loop, body)
- struct loops *loops;
- basic_block bb;
- struct loop *loop;
- basic_block *body;
+may_unswitch_on_p (struct loops *loops, basic_block bb, struct loop *loop,
+ basic_block *body)
{
rtx test;
unsigned i;
/* Reverses CONDition; returns NULL if we cannot. */
static rtx
-reversed_condition (cond)
- rtx cond;
+reversed_condition (rtx cond)
{
enum rtx_code reversed;
reversed = reversed_comparison_code (cond, NULL);
number of unswitchings done; do not allow it to grow too much, it is too
easy to create example on that the code would grow exponentially. */
static void
-unswitch_single_loop (loops, loop, cond_checked, num)
- struct loops *loops;
- struct loop *loop;
- rtx cond_checked;
- int num;
+unswitch_single_loop (struct loops *loops, struct loop *loop,
+ rtx cond_checked, int num)
{
basic_block *bbs, bb;
struct loop *nloop;
fprintf (rtl_dump_file, ";; Not unswitching, not innermost loop\n");
return;
}
-
+
/* We must be able to duplicate loop body. */
if (!can_duplicate_loop_p (loop))
{
fprintf (rtl_dump_file, ";; Not unswitching, loop too big\n");
return;
}
-
+
/* Do not unswitch in cold areas. */
if (!maybe_hot_bb_p (loop->header))
{
fprintf (rtl_dump_file, ";; Not unswitching, not hot area\n");
return;
}
-
+
/* Nor if the loop usually does not roll. */
if (expected_loop_iterations (loop) < 1)
{
do
{
repeat = 0;
-
+
/* Find a bb to unswitch on. */
bbs = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
if (!(cond = get_condition (bbs[i]->end, &split_before)))
abort ();
rcond = reversed_condition (cond);
-
+
/* Check whether the result can be predicted. */
always_true = 0;
always_false = 0;
if (always_true)
{
/* Remove false path. */
- for (e = bbs[i]->succ; !(e->flags & EDGE_FALLTHRU); e = e->succ_next);
+ for (e = bbs[i]->succ; !(e->flags & EDGE_FALLTHRU); e = e->succ_next);
remove_path (loops, e);
free (bbs);
repeat = 1;
repeat = 1;
}
} while (repeat);
-
+
/* We found the condition we can unswitch on. */
conds = alloc_EXPR_LIST (0, cond, cond_checked);
if (rcond)
for the condition we unswitch on. Returns NULL if impossible, new
loop otherwise. */
static struct loop *
-unswitch_loop (loops, loop, unswitch_on)
- struct loops *loops;
- struct loop *loop;
- basic_block unswitch_on;
+unswitch_loop (struct loops *loops, struct loop *loop, basic_block unswitch_on)
{
edge entry, latch_edge;
basic_block switch_bb, unswitch_on_alt, src;
abort ();
if (!flow_bb_inside_loop_p (loop, unswitch_on->succ->succ_next->dest))
abort ();
-
+
/* Will we be able to perform redirection? */
if (!any_condjump_p (unswitch_on->end))
return NULL;
return NULL;
entry = loop_preheader_edge (loop);
-
+
/* Make a copy. */
src = entry->src;
irred_flag = entry->flags & EDGE_IRREDUCIBLE_LOOP;