static bool
bb_no_side_effects_p (basic_block bb)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
if (is_gimple_debug (stmt))
continue;
if (gimple_has_side_effects (stmt)
|| gimple_uses_undefined_value_p (stmt)
|| gimple_could_trap_p (stmt)
|| gimple_vuse (stmt)
/* const calls don't match any of the above, yet they could
still have some side-effects - they could contain
gimple_could_trap_p statements, like floating point
exceptions or integer division by zero. See PR70586.
FIXME: perhaps gimple_has_side_effects or gimple_could_trap_p
should handle this. */
|| is_gimple_call (stmt))
return false;
}
return true;
}
static edge
loop_edge_to_cancel (struct loop *loop)
{
vec<edge> exits;
unsigned i;
edge edge_to_cancel;
gimple_stmt_iterator gsi;
/* We want only one predecestor of the loop. */
if (EDGE_COUNT (loop->latch->preds) > 1)
return NULL;
exits = get_loop_exit_edges (loop);
FOR_EACH_VEC_ELT (exits, i, edge_to_cancel)
{
/* Find the other edge than the loop exit
leaving the conditoinal. */
if (EDGE_COUNT (edge_to_cancel->src->succs) != 2)
continue;
if (EDGE_SUCC (edge_to_cancel->src, 0) == edge_to_cancel)
edge_to_cancel = EDGE_SUCC (edge_to_cancel->src, 1);
else
edge_to_cancel = EDGE_SUCC (edge_to_cancel->src, 0);
/* We only can handle conditionals. */
if (!(edge_to_cancel->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
continue;
/* We should never have conditionals in the loop latch. */
gcc_assert (edge_to_cancel->dest != loop->header);
/* Check that it leads to loop latch. */
if (edge_to_cancel->dest != loop->latch)
continue;
exits.release ();
/* Verify that the code in loop latch does nothing that may end program
execution without really reaching the exit. This may include
non-pure/const function calls, EH statements, volatile ASMs etc. */
for (gsi = gsi_start_bb (loop->latch); !gsi_end_p (gsi); gsi_next (&gsi))
if (gimple_has_side_effects (gsi_stmt (gsi)))
return NULL;
return edge_to_cancel;
}
exits.release ();
return NULL;
}
static bool
bb_no_side_effects_p (basic_block bb)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
if (gimple_has_side_effects (stmt)
|| gimple_vuse (stmt))
return false;
}
return true;
}
static bool
tree_estimate_loop_size (struct loop *loop, edge exit, edge edge_to_cancel, struct loop_size *size,
int upper_bound)
{
basic_block *body = get_loop_body (loop);
gimple_stmt_iterator gsi;
unsigned int i;
bool after_exit;
vec<basic_block> path = get_loop_hot_path (loop);
size->overall = 0;
size->eliminated_by_peeling = 0;
size->last_iteration = 0;
size->last_iteration_eliminated_by_peeling = 0;
size->num_pure_calls_on_hot_path = 0;
size->num_non_pure_calls_on_hot_path = 0;
size->non_call_stmts_on_hot_path = 0;
size->num_branches_on_hot_path = 0;
size->constant_iv = 0;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Estimating sizes for loop %i\n", loop->num);
for (i = 0; i < loop->num_nodes; i++)
{
if (edge_to_cancel && body[i] != edge_to_cancel->src
&& dominated_by_p (CDI_DOMINATORS, body[i], edge_to_cancel->src))
after_exit = true;
else
after_exit = false;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " BB: %i, after_exit: %i\n", body[i]->index, after_exit);
for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
int num = estimate_num_insns (stmt, &eni_size_weights);
bool likely_eliminated = false;
bool likely_eliminated_last = false;
bool likely_eliminated_peeled = false;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " size: %3i ", num);
print_gimple_stmt (dump_file, gsi_stmt (gsi), 0, 0);
}
/* Look for reasons why we might optimize this stmt away. */
if (gimple_has_side_effects (stmt))
;
/* Exit conditional. */
else if (exit && body[i] == exit->src
&& stmt == last_stmt (exit->src))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Exit condition will be eliminated "
"in peeled copies.\n");
likely_eliminated_peeled = true;
}
else if (edge_to_cancel && body[i] == edge_to_cancel->src
&& stmt == last_stmt (edge_to_cancel->src))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Exit condition will be eliminated "
"in last copy.\n");
likely_eliminated_last = true;
}
/* Sets of IV variables */
else if (gimple_code (stmt) == GIMPLE_ASSIGN
&& constant_after_peeling (gimple_assign_lhs (stmt), stmt, loop))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Induction variable computation will"
" be folded away.\n");
likely_eliminated = true;
}
/* Assignments of IV variables. */
else if (gimple_code (stmt) == GIMPLE_ASSIGN
&& TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME
&& constant_after_peeling (gimple_assign_rhs1 (stmt), stmt, loop)
&& (gimple_assign_rhs_class (stmt) != GIMPLE_BINARY_RHS
|| constant_after_peeling (gimple_assign_rhs2 (stmt),
stmt, loop)))
{
size->constant_iv = true;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Constant expression will be folded away.\n");
likely_eliminated = true;
}
/* Conditionals. */
else if ((gimple_code (stmt) == GIMPLE_COND
&& constant_after_peeling (gimple_cond_lhs (stmt), stmt, loop)
&& constant_after_peeling (gimple_cond_rhs (stmt), stmt, loop)
/* We don't simplify all constant compares so make sure
they are not both constant already. See PR70288. */
&& (! is_gimple_min_invariant (gimple_cond_lhs (stmt))
|| ! is_gimple_min_invariant (gimple_cond_rhs (stmt))))
|| (gimple_code (stmt) == GIMPLE_SWITCH
&& constant_after_peeling (gimple_switch_index (
as_a <gswitch *> (stmt)),
stmt, loop)
&& ! is_gimple_min_invariant (gimple_switch_index (
as_a <gswitch *> (stmt)))))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Constant conditional.\n");
likely_eliminated = true;
}
size->overall += num;
if (likely_eliminated || likely_eliminated_peeled)
size->eliminated_by_peeling += num;
if (!after_exit)
{
size->last_iteration += num;
if (likely_eliminated || likely_eliminated_last)
size->last_iteration_eliminated_by_peeling += num;
}
if ((size->overall * 3 / 2 - size->eliminated_by_peeling
- size->last_iteration_eliminated_by_peeling) > upper_bound)
{
free (body);
path.release ();
return true;
}
}
}
while (path.length ())
{
basic_block bb = path.pop ();
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
if (gimple_code (stmt) == GIMPLE_CALL)
{
int flags = gimple_call_flags (stmt);
tree decl = gimple_call_fndecl (stmt);
if (decl && DECL_IS_BUILTIN (decl)
&& is_inexpensive_builtin (decl))
;
else if (flags & (ECF_PURE | ECF_CONST))
size->num_pure_calls_on_hot_path++;
else
size->num_non_pure_calls_on_hot_path++;
size->num_branches_on_hot_path ++;
}
else if (gimple_code (stmt) != GIMPLE_CALL
&& gimple_code (stmt) != GIMPLE_DEBUG)
size->non_call_stmts_on_hot_path++;
if (((gimple_code (stmt) == GIMPLE_COND
&& (!constant_after_peeling (gimple_cond_lhs (stmt), stmt, loop)
|| constant_after_peeling (gimple_cond_rhs (stmt), stmt, loop)))
|| (gimple_code (stmt) == GIMPLE_SWITCH
&& !constant_after_peeling (gimple_switch_index (
as_a <gswitch *> (stmt)),
stmt, loop)))
&& (!exit || bb != exit->src))
size->num_branches_on_hot_path++;
}
}
path.release ();
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "size: %i-%i, last_iteration: %i-%i\n", size->overall,
size->eliminated_by_peeling, size->last_iteration,
size->last_iteration_eliminated_by_peeling);
free (body);
return false;
}