/* Initialization of the RTL loop passes. */
static void
rtl_loop_init (void)
{
if (dump_file)
dump_flow_info (dump_file);
/* Initialize structures for layout changes. */
cfg_layout_initialize (0);
current_loops = loop_optimizer_init (dump_file);
}
/* 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;
}
static unsigned int
tree_ssa_loop_init (void)
{
loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS);
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
if (number_of_loops () <= 1)
return 0;
scev_initialize ();
return 0;
}
static unsigned int
tree_ssa_cs_elim (void)
{
unsigned todo;
/* ??? We are not interested in loop related info, but the following
will create it, ICEing as we didn't init loops with pre-headers.
An interfacing issue of find_data_references_in_bb. */
loop_optimizer_init (LOOPS_NORMAL);
scev_initialize ();
todo = tree_ssa_phiopt_worker (true, false);
scev_finalize ();
loop_optimizer_finalize ();
return todo;
}
/* Initialization of the RTL loop passes. */
static unsigned int
rtl_loop_init (void)
{
gcc_assert (current_ir_type () == IR_RTL_CFGLAYOUT);
if (dump_file)
{
dump_reg_info (dump_file);
dump_flow_info (dump_file, dump_flags);
}
loop_optimizer_init (LOOPS_NORMAL);
return 0;
}
static struct loops *
tree_loop_optimizer_init (void)
{
struct loops *loops;
loops = loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_MARKED_SINGLE_EXITS);
if (!loops)
return NULL;
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
return loops;
}
static unsigned int
tree_ssa_loop_init (void)
{
loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS);
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
/* We might discover new loops, e.g. when turning irreducible
regions into reducible. */
scev_initialize ();
if (number_of_loops (cfun) <= 1)
return 0;
return 0;
}
static unsigned int
tree_complete_unroll_inner (void)
{
unsigned ret = 0;
loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS);
if (number_of_loops () > 1)
{
scev_initialize ();
ret = tree_unroll_loops_completely (optimize >= 3, false);
free_numbers_of_iterations_estimates ();
scev_finalize ();
}
loop_optimizer_finalize ();
return ret;
}
static bool
split_paths ()
{
bool changed = false;
loop_p loop;
loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
initialize_original_copy_tables ();
calculate_dominance_info (CDI_DOMINATORS);
FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
{
/* Only split paths if we are optimizing this loop for speed. */
if (!optimize_loop_for_speed_p (loop))
continue;
/* See if there is a block that we can duplicate to split the
path to the loop latch. */
basic_block bb
= find_block_to_duplicate_for_splitting_paths (loop->latch);
/* BB is the merge point for an IF-THEN-ELSE we want to transform.
Essentially we want to create a duplicate of bb and redirect the
first predecessor of BB to the duplicate (leaving the second
predecessor as is. This will split the path leading to the latch
re-using BB to avoid useless copying. */
if (bb && is_feasible_trace (bb))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Duplicating join block %d into predecessor paths\n",
bb->index);
basic_block pred0 = EDGE_PRED (bb, 0)->src;
transform_duplicate (pred0, bb);
changed = true;
}
}
loop_optimizer_finalize ();
free_original_copy_tables ();
return changed;
}
static funct_state
analyze_function (struct cgraph_node *fn, bool ipa)
{
tree decl = fn->symbol.decl;
funct_state l;
basic_block this_block;
l = XCNEW (struct funct_state_d);
l->pure_const_state = IPA_CONST;
l->state_previously_known = IPA_NEITHER;
l->looping_previously_known = true;
l->looping = false;
l->can_throw = false;
state_from_flags (&l->state_previously_known, &l->looping_previously_known,
flags_from_decl_or_type (fn->symbol.decl),
cgraph_node_cannot_return (fn));
if (fn->thunk.thunk_p || fn->symbol.alias)
{
/* Thunk gets propagated through, so nothing interesting happens. */
gcc_assert (ipa);
return l;
}
if (dump_file)
{
fprintf (dump_file, "\n\n local analysis of %s\n ",
cgraph_node_name (fn));
}
push_cfun (DECL_STRUCT_FUNCTION (decl));
FOR_EACH_BB (this_block)
{
gimple_stmt_iterator gsi;
struct walk_stmt_info wi;
memset (&wi, 0, sizeof(wi));
for (gsi = gsi_start_bb (this_block);
!gsi_end_p (gsi);
gsi_next (&gsi))
{
check_stmt (&gsi, l, ipa);
if (l->pure_const_state == IPA_NEITHER && l->looping && l->can_throw)
goto end;
}
}
end:
if (l->pure_const_state != IPA_NEITHER)
{
/* Const functions cannot have back edges (an
indication of possible infinite loop side
effect. */
if (mark_dfs_back_edges ())
{
/* Preheaders are needed for SCEV to work.
Simple latches and recorded exits improve chances that loop will
proved to be finite in testcases such as in loop-15.c
and loop-24.c */
loop_optimizer_init (LOOPS_HAVE_PREHEADERS
| LOOPS_HAVE_SIMPLE_LATCHES
| LOOPS_HAVE_RECORDED_EXITS);
if (dump_file && (dump_flags & TDF_DETAILS))
flow_loops_dump (dump_file, NULL, 0);
if (mark_irreducible_loops ())
{
if (dump_file)
fprintf (dump_file, " has irreducible loops\n");
l->looping = true;
}
else
{
loop_iterator li;
struct loop *loop;
scev_initialize ();
FOR_EACH_LOOP (li, loop, 0)
if (!finite_loop_p (loop))
{
if (dump_file)
fprintf (dump_file, " can not prove finiteness of "
"loop %i\n", loop->num);
l->looping =true;
FOR_EACH_LOOP_BREAK (li);
}
scev_finalize ();
}
loop_optimizer_finalize ();
}
}
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " checking previously known:");
better_state (&l->pure_const_state, &l->looping,
l->state_previously_known,
l->looping_previously_known);
if (TREE_NOTHROW (decl))
l->can_throw = false;
pop_cfun ();
if (dump_file)
{
if (l->looping)
fprintf (dump_file, "Function is locally looping.\n");
if (l->can_throw)
fprintf (dump_file, "Function is locally throwing.\n");
if (l->pure_const_state == IPA_CONST)
fprintf (dump_file, "Function is locally const.\n");
if (l->pure_const_state == IPA_PURE)
fprintf (dump_file, "Function is locally pure.\n");
}
return l;
}
static bool
split_paths ()
{
bool changed = false;
loop_p loop;
loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
initialize_original_copy_tables ();
calculate_dominance_info (CDI_DOMINATORS);
FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
{
/* Only split paths if we are optimizing this loop for speed. */
if (!optimize_loop_for_speed_p (loop))
continue;
/* See if there is a block that we can duplicate to split the
path to the loop latch. */
basic_block bb
= find_block_to_duplicate_for_splitting_paths (loop->latch);
/* BB is the merge point for an IF-THEN-ELSE we want to transform.
Essentially we want to create a duplicate of bb and redirect the
first predecessor of BB to the duplicate (leaving the second
predecessor as is. This will split the path leading to the latch
re-using BB to avoid useless copying. */
if (bb && is_feasible_trace (bb))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Duplicating join block %d into predecessor paths\n",
bb->index);
basic_block pred0 = EDGE_PRED (bb, 0)->src;
transform_duplicate (pred0, bb);
changed = true;
/* If BB has an outgoing edge marked as IRREDUCIBLE, then
duplicating BB may result in an irreducible region turning
into a natural loop.
Long term we might want to hook this into the block
duplication code, but as we've seen with similar changes
for edge removal, that can be somewhat risky. */
if (EDGE_SUCC (bb, 0)->flags & EDGE_IRREDUCIBLE_LOOP
|| EDGE_SUCC (bb, 1)->flags & EDGE_IRREDUCIBLE_LOOP)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Join block %d has EDGE_IRREDUCIBLE_LOOP set. "
"Scheduling loop fixups.\n",
bb->index);
loops_state_set (LOOPS_NEED_FIXUP);
}
}
}
loop_optimizer_finalize ();
free_original_copy_tables ();
return changed;
}
static void
copy_loop_headers (void)
{
struct loops *loops;
unsigned i;
struct loop *loop;
basic_block header;
edge exit;
basic_block *bbs;
unsigned n_bbs;
loops = loop_optimizer_init (dump_file);
if (!loops)
return;
rewrite_into_loop_closed_ssa ();
/* We do not try to keep the information about irreducible regions
up-to-date. */
loops->state &= ~LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS;
#ifdef ENABLE_CHECKING
verify_loop_structure (loops);
#endif
bbs = xmalloc (sizeof (basic_block) * n_basic_blocks);
for (i = 1; i < loops->num; i++)
{
/* Copy at most 20 insns. */
int limit = 20;
loop = loops->parray[i];
if (!loop)
continue;
header = loop->header;
/* If the loop is already a do-while style one (either because it was
written as such, or because jump threading transformed it into one),
we might be in fact peeling the first iteration of the loop. This
in general is not a good idea. */
if (do_while_loop_p (loop))
continue;
/* Iterate the header copying up to limit; this takes care of the cases
like while (a && b) {...}, where we want to have both of the conditions
copied. TODO -- handle while (a || b) - like cases, by not requiring
the header to have just a single successor and copying up to
postdominator. */
exit = NULL;
n_bbs = 0;
while (should_duplicate_loop_header_p (header, loop, &limit))
{
/* Find a successor of header that is inside a loop; i.e. the new
header after the condition is copied. */
if (flow_bb_inside_loop_p (loop, EDGE_SUCC (header, 0)->dest))
exit = EDGE_SUCC (header, 0);
else
exit = EDGE_SUCC (header, 1);
bbs[n_bbs++] = header;
header = exit->dest;
}
if (!exit)
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Duplicating header of the loop %d up to edge %d->%d.\n",
loop->num, exit->src->index, exit->dest->index);
/* Ensure that the header will have just the latch as a predecessor
inside the loop. */
if (EDGE_COUNT (exit->dest->preds) > 1)
exit = EDGE_SUCC (loop_split_edge_with (exit, NULL), 0);
if (!tree_duplicate_sese_region (loop_preheader_edge (loop), exit,
bbs, n_bbs, NULL))
{
fprintf (dump_file, "Duplication failed.\n");
continue;
}
/* Ensure that the latch and the preheader is simple (we know that they
are not now, since there was the loop exit condition. */
loop_split_edge_with (loop_preheader_edge (loop), NULL);
loop_split_edge_with (loop_latch_edge (loop), NULL);
}
free (bbs);
#ifdef ENABLE_CHECKING
verify_loop_closed_ssa ();
#endif
loop_optimizer_finalize (loops, NULL);
}
static unsigned int
copy_loop_headers (void)
{
struct loops *loops;
unsigned i;
struct loop *loop;
basic_block header;
edge exit, entry;
basic_block *bbs, *copied_bbs;
unsigned n_bbs;
unsigned bbs_size;
loops = loop_optimizer_init (LOOPS_HAVE_PREHEADERS
| LOOPS_HAVE_SIMPLE_LATCHES);
if (!loops)
return 0;
#ifdef ENABLE_CHECKING
verify_loop_structure (loops);
#endif
bbs = XNEWVEC (basic_block, n_basic_blocks);
copied_bbs = XNEWVEC (basic_block, n_basic_blocks);
bbs_size = n_basic_blocks;
for (i = 1; i < loops->num; i++)
{
/* Copy at most 20 insns. */
int limit = 20;
loop = loops->parray[i];
if (!loop)
continue;
header = loop->header;
/* If the loop is already a do-while style one (either because it was
written as such, or because jump threading transformed it into one),
we might be in fact peeling the first iteration of the loop. This
in general is not a good idea. */
if (do_while_loop_p (loop))
continue;
/* Iterate the header copying up to limit; this takes care of the cases
like while (a && b) {...}, where we want to have both of the conditions
copied. TODO -- handle while (a || b) - like cases, by not requiring
the header to have just a single successor and copying up to
postdominator. */
exit = NULL;
n_bbs = 0;
while (should_duplicate_loop_header_p (header, loop, &limit))
{
/* Find a successor of header that is inside a loop; i.e. the new
header after the condition is copied. */
if (flow_bb_inside_loop_p (loop, EDGE_SUCC (header, 0)->dest))
exit = EDGE_SUCC (header, 0);
else
exit = EDGE_SUCC (header, 1);
bbs[n_bbs++] = header;
gcc_assert (bbs_size > n_bbs);
header = exit->dest;
}
if (!exit)
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Duplicating header of the loop %d up to edge %d->%d.\n",
loop->num, exit->src->index, exit->dest->index);
/* Ensure that the header will have just the latch as a predecessor
inside the loop. */
if (!single_pred_p (exit->dest))
exit = single_pred_edge (loop_split_edge_with (exit, NULL));
entry = loop_preheader_edge (loop);
if (!tree_duplicate_sese_region (entry, exit, bbs, n_bbs, copied_bbs))
{
fprintf (dump_file, "Duplication failed.\n");
continue;
}
/* If the loop has the form "for (i = j; i < j + 10; i++)" then
this copying can introduce a case where we rely on undefined
signed overflow to eliminate the preheader condition, because
we assume that "j < j + 10" is true. We don't want to warn
about that case for -Wstrict-overflow, because in general we
don't warn about overflow involving loops. Prevent the
warning by setting TREE_NO_WARNING. */
if (warn_strict_overflow > 0)
{
unsigned int i;
for (i = 0; i < n_bbs; ++i)
{
tree last;
last = last_stmt (copied_bbs[i]);
if (TREE_CODE (last) == COND_EXPR)
TREE_NO_WARNING (last) = 1;
}
}
/* Ensure that the latch and the preheader is simple (we know that they
are not now, since there was the loop exit condition. */
loop_split_edge_with (loop_preheader_edge (loop), NULL);
loop_split_edge_with (loop_latch_edge (loop), NULL);
}
free (bbs);
free (copied_bbs);
loop_optimizer_finalize (loops);
return 0;
}
