static bool
remove_exits_and_undefined_stmts (struct loop *loop, unsigned int npeeled)
{
struct nb_iter_bound *elt;
bool changed = false;
for (elt = loop->bounds; elt; elt = elt->next)
{
/* If statement is known to be undefined after peeling, turn it
into unreachable (or trap when debugging experience is supposed
to be good). */
if (!elt->is_exit
&& wi::ltu_p (elt->bound, npeeled))
{
gimple_stmt_iterator gsi = gsi_for_stmt (elt->stmt);
gcall *stmt = gimple_build_call
(builtin_decl_implicit (BUILT_IN_UNREACHABLE), 0);
gimple_set_location (stmt, gimple_location (elt->stmt));
gsi_insert_before (&gsi, stmt, GSI_NEW_STMT);
split_block (gimple_bb (stmt), stmt);
changed = true;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Forced statement unreachable: ");
print_gimple_stmt (dump_file, elt->stmt, 0, 0);
}
}
/* If we know the exit will be taken after peeling, update. */
else if (elt->is_exit
&& wi::leu_p (elt->bound, npeeled))
{
basic_block bb = gimple_bb (elt->stmt);
edge exit_edge = EDGE_SUCC (bb, 0);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Forced exit to be taken: ");
print_gimple_stmt (dump_file, elt->stmt, 0, 0);
}
if (!loop_exit_edge_p (loop, exit_edge))
exit_edge = EDGE_SUCC (bb, 1);
gcc_checking_assert (loop_exit_edge_p (loop, exit_edge));
gcond *cond_stmt = as_a <gcond *> (elt->stmt);
if (exit_edge->flags & EDGE_TRUE_VALUE)
gimple_cond_make_true (cond_stmt);
else
gimple_cond_make_false (cond_stmt);
update_stmt (cond_stmt);
changed = true;
}
}
return changed;
}
static bool
remove_redundant_iv_tests (struct loop *loop)
{
struct nb_iter_bound *elt;
bool changed = false;
if (!loop->any_upper_bound)
return false;
for (elt = loop->bounds; elt; elt = elt->next)
{
/* Exit is pointless if it won't be taken before loop reaches
upper bound. */
if (elt->is_exit && loop->any_upper_bound
&& wi::ltu_p (loop->nb_iterations_upper_bound, elt->bound))
{
basic_block bb = gimple_bb (elt->stmt);
edge exit_edge = EDGE_SUCC (bb, 0);
struct tree_niter_desc niter;
if (!loop_exit_edge_p (loop, exit_edge))
exit_edge = EDGE_SUCC (bb, 1);
/* Only when we know the actual number of iterations, not
just a bound, we can remove the exit. */
if (!number_of_iterations_exit (loop, exit_edge,
&niter, false, false)
|| !integer_onep (niter.assumptions)
|| !integer_zerop (niter.may_be_zero)
|| !niter.niter
|| TREE_CODE (niter.niter) != INTEGER_CST
|| !wi::ltu_p (loop->nb_iterations_upper_bound,
wi::to_widest (niter.niter)))
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Removed pointless exit: ");
print_gimple_stmt (dump_file, elt->stmt, 0, 0);
}
gcond *cond_stmt = as_a <gcond *> (elt->stmt);
if (exit_edge->flags & EDGE_TRUE_VALUE)
gimple_cond_make_false (cond_stmt);
else
gimple_cond_make_true (cond_stmt);
update_stmt (cond_stmt);
changed = true;
}
}
return changed;
}
static enum ssa_prop_result
copy_prop_visit_phi_node (gimple phi)
{
enum ssa_prop_result retval;
unsigned i;
prop_value_t phi_val = { NULL_TREE };
tree lhs = gimple_phi_result (phi);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\nVisiting PHI node: ");
print_gimple_stmt (dump_file, phi, 0, dump_flags);
}
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
prop_value_t *arg_val;
tree arg_value;
tree arg = gimple_phi_arg_def (phi, i);
edge e = gimple_phi_arg_edge (phi, i);
/* We don't care about values flowing through non-executable
edges. */
if (!(e->flags & EDGE_EXECUTABLE))
continue;
/* Names that flow through abnormal edges cannot be used to
derive copies. */
if (TREE_CODE (arg) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (arg))
{
phi_val.value = lhs;
break;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\tArgument #%d: ", i);
dump_copy_of (dump_file, arg);
fprintf (dump_file, "\n");
}
if (TREE_CODE (arg) == SSA_NAME)
{
arg_val = get_copy_of_val (arg);
/* If we didn't visit the definition of arg yet treat it as
UNDEFINED. This also handles PHI arguments that are the
same as lhs. We'll come here again. */
if (!arg_val->value)
continue;
arg_value = arg_val->value;
}
else
arg_value = valueize_val (arg);
/* Avoid copy propagation from an inner into an outer loop.
Otherwise, this may move loop variant variables outside of
their loops and prevent coalescing opportunities. If the
value was loop invariant, it will be hoisted by LICM and
exposed for copy propagation.
??? The value will be always loop invariant.
In loop-closed SSA form do not copy-propagate through
PHI nodes in blocks with a loop exit edge predecessor. */
if (current_loops
&& TREE_CODE (arg_value) == SSA_NAME
&& (loop_depth_of_name (arg_value) > loop_depth_of_name (lhs)
|| (loops_state_satisfies_p (LOOP_CLOSED_SSA)
&& loop_exit_edge_p (e->src->loop_father, e))))
{
phi_val.value = lhs;
break;
}
/* If the LHS didn't have a value yet, make it a copy of the
first argument we find. */
if (phi_val.value == NULL_TREE)
{
phi_val.value = arg_value;
continue;
}
/* If PHI_VAL and ARG don't have a common copy-of chain, then
this PHI node cannot be a copy operation. */
if (phi_val.value != arg_value
&& !operand_equal_p (phi_val.value, arg_value, 0))
{
phi_val.value = lhs;
break;
}
}
if (phi_val.value
&& may_propagate_copy (lhs, phi_val.value)
&& set_copy_of_val (lhs, phi_val.value))
retval = (phi_val.value != lhs) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
else
retval = SSA_PROP_NOT_INTERESTING;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "PHI node ");
dump_copy_of (dump_file, lhs);
fprintf (dump_file, "\nTelling the propagator to ");
if (retval == SSA_PROP_INTERESTING)
fprintf (dump_file, "add SSA edges out of this PHI and continue.");
else if (retval == SSA_PROP_VARYING)
fprintf (dump_file, "add SSA edges out of this PHI and never visit again.");
else
fprintf (dump_file, "do nothing with SSA edges and keep iterating.");
fprintf (dump_file, "\n\n");
}
return retval;
}
