static unsigned int
execute_return_slot_opt (void)
{
basic_block bb;
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
{
tree stmt = bsi_stmt (i);
tree call;
if (TREE_CODE (stmt) == MODIFY_EXPR
&& (call = TREE_OPERAND (stmt, 1),
TREE_CODE (call) == CALL_EXPR)
&& !CALL_EXPR_RETURN_SLOT_OPT (call)
&& aggregate_value_p (call, call))
/* Check if the location being assigned to is
call-clobbered. */
CALL_EXPR_RETURN_SLOT_OPT (call) =
dest_safe_for_nrv_p (TREE_OPERAND (stmt, 0)) ? 1 : 0;
}
}
return 0;
}
static unsigned int
execute_return_slot_opt (void)
{
basic_block bb;
FOR_EACH_BB_FN (bb, cfun)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
bool slot_opt_p;
if (is_gimple_call (stmt)
&& gimple_call_lhs (stmt)
&& !gimple_call_return_slot_opt_p (stmt)
&& aggregate_value_p (TREE_TYPE (gimple_call_lhs (stmt)),
gimple_call_fndecl (stmt)))
{
/* Check if the location being assigned to is
clobbered by the call. */
slot_opt_p = dest_safe_for_nrv_p (stmt);
gimple_call_set_return_slot_opt (stmt, slot_opt_p);
}
}
}
static bool
dest_safe_for_nrv_p (tree dest)
{
switch (TREE_CODE (dest))
{
case VAR_DECL:
{
subvar_t subvar;
if (is_call_clobbered (dest))
return false;
for (subvar = get_subvars_for_var (dest);
subvar;
subvar = subvar->next)
if (is_call_clobbered (subvar->var))
return false;
return true;
}
case ARRAY_REF:
case COMPONENT_REF:
return dest_safe_for_nrv_p (TREE_OPERAND (dest, 0));
default:
return false;
}
}
