bool
may_propagate_copy_into_stmt (gimple dest, tree orig)
{
tree type_d;
tree type_o;
/* If the statement is a switch or a single-rhs assignment,
then the expression to be replaced by the propagation may
be an SSA_NAME. Fortunately, there is an explicit tree
for the expression, so we delegate to may_propagate_copy. */
if (gimple_assign_single_p (dest))
return may_propagate_copy (gimple_assign_rhs1 (dest), orig);
else if (gimple_code (dest) == GIMPLE_SWITCH)
return may_propagate_copy (gimple_switch_index (dest), orig);
/* In other cases, the expression is not materialized, so there
is no destination to pass to may_propagate_copy. On the other
hand, the expression cannot be an SSA_NAME, so the analysis
is much simpler. */
if (TREE_CODE (orig) == SSA_NAME
&& (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)
|| TREE_CODE (SSA_NAME_VAR (orig)) == MEMORY_PARTITION_TAG))
return false;
if (is_gimple_assign (dest))
type_d = TREE_TYPE (gimple_assign_lhs (dest));
else if (gimple_code (dest) == GIMPLE_COND)
type_d = boolean_type_node;
else if (is_gimple_call (dest)
&& gimple_call_lhs (dest) != NULL_TREE)
type_d = TREE_TYPE (gimple_call_lhs (dest));
else
gcc_unreachable ();
type_o = TREE_TYPE (orig);
if (!useless_type_conversion_p (type_d, type_o))
return false;
return true;
}
void
propagate_tree_value (tree *op_p, tree val)
{
gcc_checking_assert (!(TREE_CODE (val) == SSA_NAME
&& *op_p
&& TREE_CODE (*op_p) == SSA_NAME
&& !may_propagate_copy (*op_p, val)));
if (TREE_CODE (val) == SSA_NAME)
*op_p = val;
else
*op_p = unsave_expr_now (val);
}
void
propagate_tree_value (tree *op_p, tree val)
{
#if defined ENABLE_CHECKING
gcc_assert (!(TREE_CODE (val) == SSA_NAME
&& *op_p
&& TREE_CODE (*op_p) == SSA_NAME
&& !may_propagate_copy (*op_p, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
*op_p = val;
else
*op_p = unsave_expr_now (val);
}
static void
replace_exp_1 (use_operand_p op_p, tree val,
bool for_propagation ATTRIBUTE_UNUSED)
{
#if defined ENABLE_CHECKING
tree op = USE_FROM_PTR (op_p);
gcc_assert (!(for_propagation
&& TREE_CODE (op) == SSA_NAME
&& TREE_CODE (val) == SSA_NAME
&& !may_propagate_copy (op, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
SET_USE (op_p, val);
else
SET_USE (op_p, unsave_expr_now (val));
}
void
propagate_tree_value (tree *op_p, tree val)
{
#if defined ENABLE_CHECKING
gcc_assert (!(TREE_CODE (val) == SSA_NAME
&& *op_p
&& TREE_CODE (*op_p) == SSA_NAME
&& !may_propagate_copy (*op_p, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
{
if (*op_p && TREE_CODE (*op_p) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (*op_p)))
merge_alias_info (*op_p, val);
*op_p = val;
}
else
*op_p = unsave_expr_now (val);
}
static void
replace_exp_1 (use_operand_p op_p, tree val,
bool for_propagation ATTRIBUTE_UNUSED)
{
tree op = USE_FROM_PTR (op_p);
#if defined ENABLE_CHECKING
gcc_assert (!(for_propagation
&& TREE_CODE (op) == SSA_NAME
&& TREE_CODE (val) == SSA_NAME
&& !may_propagate_copy (op, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
{
if (TREE_CODE (op) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (op)))
merge_alias_info (op, val);
SET_USE (op_p, val);
}
else
SET_USE (op_p, unsave_expr_now (val));
}
static enum ssa_prop_result
copy_prop_visit_assignment (gimple stmt, tree *result_p)
{
tree lhs, rhs;
lhs = gimple_assign_lhs (stmt);
rhs = valueize_val (gimple_assign_rhs1 (stmt));
if (TREE_CODE (lhs) == SSA_NAME)
{
/* Straight copy between two SSA names. First, make sure that
we can propagate the RHS into uses of LHS. */
if (!may_propagate_copy (lhs, rhs))
return SSA_PROP_VARYING;
*result_p = lhs;
if (set_copy_of_val (*result_p, rhs))
return SSA_PROP_INTERESTING;
else
return SSA_PROP_NOT_INTERESTING;
}
return SSA_PROP_VARYING;
}
static enum ssa_prop_result
copy_prop_visit_assignment (gimple stmt, tree *result_p)
{
tree lhs, rhs;
prop_value_t *rhs_val;
lhs = gimple_assign_lhs (stmt);
rhs = gimple_assign_rhs1 (stmt);
gcc_assert (gimple_assign_rhs_code (stmt) == SSA_NAME);
rhs_val = get_copy_of_val (rhs);
if (TREE_CODE (lhs) == SSA_NAME)
{
/* Straight copy between two SSA names. First, make sure that
we can propagate the RHS into uses of LHS. */
if (!may_propagate_copy (lhs, rhs))
return SSA_PROP_VARYING;
/* Notice that in the case of assignments, we make the LHS be a
copy of RHS's value, not of RHS itself. This avoids keeping
unnecessary copy-of chains (assignments cannot be in a cycle
like PHI nodes), speeding up the propagation process.
This is different from what we do in copy_prop_visit_phi_node.
In those cases, we are interested in the copy-of chains. */
*result_p = lhs;
if (set_copy_of_val (*result_p, rhs_val->value))
return SSA_PROP_INTERESTING;
else
return SSA_PROP_NOT_INTERESTING;
}
return SSA_PROP_VARYING;
}
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;
}
static enum ssa_prop_result
copy_prop_visit_phi_node (gimple phi)
{
enum ssa_prop_result retval;
unsigned i;
prop_value_t phi_val = { 0, 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);
fprintf (dump_file, "\n\n");
}
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
prop_value_t *arg_val;
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;
/* Constants in the argument list never generate a useful copy.
Similarly, 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;
}
/* 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. Not a problem for virtual
operands though. */
if (is_gimple_reg (lhs)
&& loop_depth_of_name (arg) > loop_depth_of_name (lhs))
{
phi_val.value = lhs;
break;
}
/* If the LHS appears in the argument list, ignore it. It is
irrelevant as a copy. */
if (arg == lhs || get_last_copy_of (arg) == lhs)
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\tArgument #%d: ", i);
dump_copy_of (dump_file, arg);
fprintf (dump_file, "\n");
}
arg_val = get_copy_of_val (arg);
/* If the LHS didn't have a value yet, make it a copy of the
first argument we find. Notice that while we make the LHS be
a copy of the argument itself, we take the memory reference
from the argument's value so that we can compare it to the
memory reference of all the other arguments. */
if (phi_val.value == NULL_TREE)
{
phi_val.value = arg_val->value ? arg_val->value : arg;
continue;
}
/* If PHI_VAL and ARG don't have a common copy-of chain, then
this PHI node cannot be a copy operation. Also, if we are
copy propagating stores and these two arguments came from
different memory references, they cannot be considered
copies. */
if (get_last_copy_of (phi_val.value) != get_last_copy_of (arg))
{
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, "\nPHI 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;
}
