static void
tree_ssa_forward_propagate_single_use_vars (void)
{
basic_block bb;
cfg_changed = false;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
/* Note we update BSI within the loop as necessary. */
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree stmt = bsi_stmt (bsi);
/* If this statement sets an SSA_NAME to an address,
try to propagate the address into the uses of the SSA_NAME. */
if (TREE_CODE (stmt) == MODIFY_EXPR
&& TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
{
if (forward_propagate_addr_expr (stmt))
bsi_remove (&bsi);
else
bsi_next (&bsi);
}
else if (TREE_CODE (stmt) == COND_EXPR)
{
forward_propagate_into_cond (stmt);
bsi_next (&bsi);
}
else
bsi_next (&bsi);
}
}
if (cfg_changed)
cleanup_tree_cfg ();
}
static bool
forward_propagate_addr_expr_1 (tree name, tree def_rhs,
gimple_stmt_iterator *use_stmt_gsi,
bool single_use_p)
{
tree lhs, rhs, rhs2, array_ref;
tree *rhsp, *lhsp;
gimple use_stmt = gsi_stmt (*use_stmt_gsi);
enum tree_code rhs_code;
gcc_assert (TREE_CODE (def_rhs) == ADDR_EXPR);
lhs = gimple_assign_lhs (use_stmt);
rhs_code = gimple_assign_rhs_code (use_stmt);
rhs = gimple_assign_rhs1 (use_stmt);
/* Trivial cases. The use statement could be a trivial copy or a
useless conversion. Recurse to the uses of the lhs as copyprop does
not copy through different variant pointers and FRE does not catch
all useless conversions. Treat the case of a single-use name and
a conversion to def_rhs type separate, though. */
if (TREE_CODE (lhs) == SSA_NAME
&& ((rhs_code == SSA_NAME && rhs == name)
|| CONVERT_EXPR_CODE_P (rhs_code)))
{
/* Only recurse if we don't deal with a single use or we cannot
do the propagation to the current statement. In particular
we can end up with a conversion needed for a non-invariant
address which we cannot do in a single statement. */
if (!single_use_p
|| (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))
&& !is_gimple_min_invariant (def_rhs)))
return forward_propagate_addr_expr (lhs, def_rhs);
gimple_assign_set_rhs1 (use_stmt, unshare_expr (def_rhs));
if (useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
gimple_assign_set_rhs_code (use_stmt, TREE_CODE (def_rhs));
else
gimple_assign_set_rhs_code (use_stmt, NOP_EXPR);
return true;
}
/* Now strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
ADDR_EXPR will not appear on the LHS. */
lhsp = gimple_assign_lhs_ptr (use_stmt);
while (handled_component_p (*lhsp))
lhsp = &TREE_OPERAND (*lhsp, 0);
lhs = *lhsp;
/* Now see if the LHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (lhs) == INDIRECT_REF
&& TREE_OPERAND (lhs, 0) == name
&& may_propagate_address_into_dereference (def_rhs, lhs)
&& (lhsp != gimple_assign_lhs_ptr (use_stmt)
|| useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
TREE_TYPE (rhs))))
{
*lhsp = unshare_expr (TREE_OPERAND (def_rhs, 0));
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
/* Continue propagating into the RHS if this was not the only use. */
if (single_use_p)
return true;
}
/* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
nodes from the RHS. */
rhsp = gimple_assign_rhs1_ptr (use_stmt);
while (handled_component_p (*rhsp)
|| TREE_CODE (*rhsp) == ADDR_EXPR)
rhsp = &TREE_OPERAND (*rhsp, 0);
rhs = *rhsp;
/* Now see if the RHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (rhs) == INDIRECT_REF
&& TREE_OPERAND (rhs, 0) == name
&& may_propagate_address_into_dereference (def_rhs, rhs))
{
*rhsp = unshare_expr (TREE_OPERAND (def_rhs, 0));
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
/* Now see if the RHS node is an INDIRECT_REF using NAME. If so,
propagate the ADDR_EXPR into the use of NAME and try to
create a VCE and fold the result. */
if (TREE_CODE (rhs) == INDIRECT_REF
&& TREE_OPERAND (rhs, 0) == name
&& TYPE_SIZE (TREE_TYPE (rhs))
&& TYPE_SIZE (TREE_TYPE (TREE_OPERAND (def_rhs, 0)))
/* Function decls should not be used for VCE either as it could be a
function descriptor that we want and not the actual function code. */
&& TREE_CODE (TREE_OPERAND (def_rhs, 0)) != FUNCTION_DECL
/* We should not convert volatile loads to non volatile loads. */
&& !TYPE_VOLATILE (TREE_TYPE (rhs))
&& !TYPE_VOLATILE (TREE_TYPE (TREE_OPERAND (def_rhs, 0)))
&& operand_equal_p (TYPE_SIZE (TREE_TYPE (rhs)),
TYPE_SIZE (TREE_TYPE (TREE_OPERAND (def_rhs, 0))), 0))
{
tree def_rhs_base, new_rhs = unshare_expr (TREE_OPERAND (def_rhs, 0));
new_rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (rhs), new_rhs);
if (TREE_CODE (new_rhs) != VIEW_CONVERT_EXPR)
{
/* If we have folded the VIEW_CONVERT_EXPR then the result is only
valid if we can replace the whole rhs of the use statement. */
if (rhs != gimple_assign_rhs1 (use_stmt))
return false;
new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs, true, NULL,
true, GSI_NEW_STMT);
gimple_assign_set_rhs1 (use_stmt, new_rhs);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
/* If the defining rhs comes from an indirect reference, then do not
convert into a VIEW_CONVERT_EXPR. */
def_rhs_base = TREE_OPERAND (def_rhs, 0);
while (handled_component_p (def_rhs_base))
def_rhs_base = TREE_OPERAND (def_rhs_base, 0);
if (!INDIRECT_REF_P (def_rhs_base))
{
/* We may have arbitrary VIEW_CONVERT_EXPRs in a nested component
reference. Place it there and fold the thing. */
*rhsp = new_rhs;
fold_stmt_inplace (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
}
/* If the use of the ADDR_EXPR is not a POINTER_PLUS_EXPR, there
is nothing to do. */
if (gimple_assign_rhs_code (use_stmt) != POINTER_PLUS_EXPR
|| gimple_assign_rhs1 (use_stmt) != name)
return false;
/* The remaining cases are all for turning pointer arithmetic into
array indexing. They only apply when we have the address of
element zero in an array. If that is not the case then there
is nothing to do. */
array_ref = TREE_OPERAND (def_rhs, 0);
if (TREE_CODE (array_ref) != ARRAY_REF
|| TREE_CODE (TREE_TYPE (TREE_OPERAND (array_ref, 0))) != ARRAY_TYPE
|| !integer_zerop (TREE_OPERAND (array_ref, 1)))
return false;
rhs2 = gimple_assign_rhs2 (use_stmt);
/* Try to optimize &x[0] p+ C where C is a multiple of the size
of the elements in X into &x[C/element size]. */
if (TREE_CODE (rhs2) == INTEGER_CST)
{
tree new_rhs = maybe_fold_stmt_addition (gimple_expr_type (use_stmt),
array_ref, rhs2);
if (new_rhs)
{
gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs);
use_stmt = gsi_stmt (*use_stmt_gsi);
update_stmt (use_stmt);
tidy_after_forward_propagate_addr (use_stmt);
return true;
}
}
/* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by
converting a multiplication of an index by the size of the
array elements, then the result is converted into the proper
type for the arithmetic. */
if (TREE_CODE (rhs2) == SSA_NAME
/* Avoid problems with IVopts creating PLUS_EXPRs with a
different type than their operands. */
&& useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs)))
return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs,
use_stmt_gsi);
return false;
}