You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
propagating NEW into ORIG, consolidate aliasing information so that
they both share the same memory tags. */
-static void
+void
merge_alias_info (tree orig, tree new)
{
tree new_sym = SSA_NAME_VAR (new);
#endif
/* Synchronize the type tags. If both pointers had a tag and they
- are different, then something has gone wrong. */
+ are different, then something has gone wrong. Type tags can
+ always be merged because they are flow insensitive, all the SSA
+ names of the same base DECL share the same type tag. */
if (new_ann->type_mem_tag == NULL_TREE)
new_ann->type_mem_tag = orig_ann->type_mem_tag;
else if (orig_ann->type_mem_tag == NULL_TREE)
else
gcc_assert (new_ann->type_mem_tag == orig_ann->type_mem_tag);
- /* Synchronize the name tags. If NEW did not have a name tag, get
- it from ORIG. This happens when NEW is a compiler generated
- temporary which still hasn't had its points-to information filled
- in. */
- if (SSA_NAME_PTR_INFO (orig))
+ /* Check that flow-sensitive information is compatible. Notice that
+ we may not merge flow-sensitive information here. This function
+ is called when propagating equivalences dictated by the IL, like
+ a copy operation P_i = Q_j, and from equivalences dictated by
+ control-flow, like if (P_i == Q_j).
+
+ In the former case, P_i and Q_j are equivalent in every block
+ dominated by the assignment, so their flow-sensitive information
+ is always the same. However, in the latter case, the pointers
+ P_i and Q_j are only equivalent in one of the sub-graphs out of
+ the predicate, so their flow-sensitive information is not the
+ same in every block dominated by the predicate.
+
+ Since we cannot distinguish one case from another in this
+ function, we can only make sure that if P_i and Q_j have
+ flow-sensitive information, they should be compatible. */
+ if (SSA_NAME_PTR_INFO (orig) && SSA_NAME_PTR_INFO (new))
{
struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig);
struct ptr_info_def *new_ptr_info = SSA_NAME_PTR_INFO (new);
- if (new_ptr_info == NULL)
- duplicate_ssa_name_ptr_info (new, orig_ptr_info);
- else if (orig_ptr_info->name_mem_tag
- && new_ptr_info->name_mem_tag
- && orig_ptr_info->pt_vars
- && new_ptr_info->pt_vars)
- {
- /* Note that pointer NEW may actually have a different set
- of pointed-to variables. However, since NEW is being
- copy-propagated into ORIG, it must always be true that
- the pointed-to set for pointer NEW is the same, or a
- subset, of the pointed-to set for pointer ORIG. If this
- isn't the case, we shouldn't have been able to do the
- propagation of NEW into ORIG. */
- gcc_assert (bitmap_intersect_p (new_ptr_info->pt_vars,
- orig_ptr_info->pt_vars));
- }
+ /* Note that pointer NEW and ORIG may actually have different
+ pointed-to variables (e.g., PR 18291 represented in
+ testsuite/gcc.c-torture/compile/pr18291.c). However, since
+ NEW is being copy-propagated into ORIG, it must always be
+ true that the pointed-to set for pointer NEW is the same, or
+ a subset, of the pointed-to set for pointer ORIG. If this
+ isn't the case, we shouldn't have been able to do the
+ propagation of NEW into ORIG. */
+ if (orig_ptr_info->name_mem_tag
+ && new_ptr_info->name_mem_tag
+ && orig_ptr_info->pt_vars
+ && new_ptr_info->pt_vars)
+ gcc_assert (bitmap_intersect_p (new_ptr_info->pt_vars,
+ orig_ptr_info->pt_vars));
}
}
/* Propagate the value VAL (assumed to be a constant or another SSA_NAME)
- into the operand pointed by OP_P.
+ into the operand pointed to by OP_P.
Use this version for const/copy propagation as it will perform additional
checks to ensure validity of the const/copy propagation. */
/* Propagate the value VAL (assumed to be a constant or another SSA_NAME)
- into the tree pointed by OP_P.
+ into the tree pointed to by OP_P.
Use this version for const/copy propagation when SSA operands are not
available. It will perform the additional checks to ensure validity of
}
-/* Initialize structures used for copy propagation. */
+/* Initialize structures used for copy propagation. PHIS_ONLY is true
+ if we should only consider PHI nodes as generating copy propagation
+ opportunities. */
static void
-init_copy_prop (void)
+init_copy_prop (bool phis_only)
{
basic_block bb;
- copy_of = xmalloc (num_ssa_names * sizeof (*copy_of));
+ copy_of = XNEWVEC (prop_value_t, num_ssa_names);
memset (copy_of, 0, num_ssa_names * sizeof (*copy_of));
- cached_last_copy_of = xmalloc (num_ssa_names * sizeof (*cached_last_copy_of));
+ cached_last_copy_of = XNEWVEC (tree, num_ssa_names);
memset (cached_last_copy_of, 0, num_ssa_names * sizeof (*cached_last_copy_of));
FOR_EACH_BB (bb)
lists of the propagator. */
if (stmt_ends_bb_p (stmt))
DONT_SIMULATE_AGAIN (stmt) = false;
- else if (stmt_may_generate_copy (stmt))
+ else if (!phis_only && stmt_may_generate_copy (stmt))
DONT_SIMULATE_AGAIN (stmt) = false;
else
{
fini_copy_prop (void)
{
size_t i;
+ prop_value_t *tmp;
/* Set the final copy-of value for each variable by traversing the
copy-of chains. */
+ tmp = XNEWVEC (prop_value_t, num_ssa_names);
+ memset (tmp, 0, num_ssa_names * sizeof (*tmp));
for (i = 1; i < num_ssa_names; i++)
{
tree var = ssa_name (i);
if (var && copy_of[i].value && copy_of[i].value != var)
- copy_of[i].value = get_last_copy_of (var);
+ tmp[i].value = get_last_copy_of (var);
}
- substitute_and_fold (copy_of, false);
+ substitute_and_fold (tmp, false);
free (cached_last_copy_of);
free (copy_of);
+ free (tmp);
}
-/* Main entry point to the copy propagator. The algorithm propagates
- the value COPY-OF using ssa_propagate. For every variable X_i,
- COPY-OF(X_i) indicates which variable is X_i created from. The
- following example shows how the algorithm proceeds at a high level:
+/* Main entry point to the copy propagator.
+
+ PHIS_ONLY is true if we should only consider PHI nodes as generating
+ copy propagation opportunities.
+
+ The algorithm propagates the value COPY-OF using ssa_propagate. For
+ every variable X_i, COPY-OF(X_i) indicates which variable is X_i created
+ from. The following example shows how the algorithm proceeds at a
+ high level:
1 a_24 = x_1
2 a_2 = PHI <a_24, x_1>
x_53 and x_54 are both copies of x_898. */
static void
-execute_copy_prop (bool store_copy_prop)
+execute_copy_prop (bool store_copy_prop, bool phis_only)
{
do_store_copy_prop = store_copy_prop;
- init_copy_prop ();
+ init_copy_prop (phis_only);
ssa_propagate (copy_prop_visit_stmt, copy_prop_visit_phi_node);
fini_copy_prop ();
}
static void
do_copy_prop (void)
{
- execute_copy_prop (false);
+ execute_copy_prop (false, false);
}
struct tree_opt_pass pass_copy_prop =
};
+static void
+do_phi_only_copy_prop (void)
+{
+ execute_copy_prop (false, true);
+}
+
+struct tree_opt_pass pass_phi_only_copy_prop =
+{
+ "phionlycopyprop", /* name */
+ gate_copy_prop, /* gate */
+ do_phi_only_copy_prop, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_COPY_PROP, /* tv_id */
+ PROP_ssa | PROP_alias | PROP_cfg, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_cleanup_cfg
+ | TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_verify_ssa
+ | TODO_update_ssa, /* todo_flags_finish */
+ 0 /* letter */
+};
+
+
static bool
gate_store_copy_prop (void)
{
store_copy_prop (void)
{
/* If STORE-COPY-PROP is not enabled, we just run regular COPY-PROP. */
- execute_copy_prop (flag_tree_store_copy_prop != 0);
+ execute_copy_prop (flag_tree_store_copy_prop != 0, false);
}
struct tree_opt_pass pass_store_copy_prop =
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