Hi,
this patch implements symmetric fix to ipa-pure-const. In this case it just
slightly
improves code quality for the case of recursive calls involving interposable
functions.
Bootstrapped/regtested x86_64-linux, comitted.
* ipa-pure-const.c (ignore_edge_for_pure_const): New function.
(propagate_pure_const): Use it; fix comments and optimize loops.
Index: ipa-pure-const.c
===================================================================
--- ipa-pure-const.c (revision 231122)
+++ ipa-pure-const.c (working copy)
@@ -1157,6 +1164,17 @@ cdtor_p (cgraph_node *n, void *)
return false;
}
+/* We only propagate across edges with non-interposable callee. */
+
+static bool
+ignore_edge_for_pure_const (struct cgraph_edge *e)
+{
+ enum availability avail;
+ e->callee->function_or_virtual_thunk_symbol (&avail);
+ return (avail <= AVAIL_INTERPOSABLE);
+}
+
+
/* Produce transitive closure over the callgraph and compute pure/const
attributes. */
@@ -1172,7 +1190,8 @@ propagate_pure_const (void)
struct ipa_dfs_info * w_info;
bool remove_p = false;
- order_pos = ipa_reduced_postorder (order, true, false, NULL);
+ order_pos = ipa_reduced_postorder (order, true, false,
+ ignore_edge_for_pure_const);
if (dump_file)
{
cgraph_node::dump_cgraph (dump_file);
@@ -1219,7 +1238,7 @@ propagate_pure_const (void)
if (pure_const_state == IPA_NEITHER)
break;
- /* For overwritable nodes we can not assume anything. */
+ /* For interposable nodes we can not assume anything. */
if (w->get_availability () == AVAIL_INTERPOSABLE)
{
worse_state (&pure_const_state, &looping,
@@ -1228,7 +1247,7 @@ propagate_pure_const (void)
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file,
- " Overwritable. state %s looping %i\n",
+ " Interposable. state %s looping %i\n",
pure_const_names[w_l->state_previously_known],
w_l->looping_previously_known);
}
@@ -1244,7 +1263,8 @@ propagate_pure_const (void)
looping = true;
/* Now walk the edges and merge in callee properties. */
- for (e = w->callees; e; e = e->next_callee)
+ for (e = w->callees; e && pure_const_state != IPA_NEITHER;
+ e = e->next_callee)
{
enum availability avail;
struct cgraph_node *y = e->callee->
@@ -1302,11 +1322,10 @@ propagate_pure_const (void)
if (pure_const_state == IPA_NEITHER)
break;
}
- if (pure_const_state == IPA_NEITHER)
- break;
/* Now process the indirect call. */
- for (ie = w->indirect_calls; ie; ie = ie->next_callee)
+ for (ie = w->indirect_calls;
+ ie && pure_const_state != IPA_NEITHER; ie = ie->next_callee)
{
enum pure_const_state_e edge_state = IPA_CONST;
bool edge_looping = false;
@@ -1325,11 +1344,10 @@ propagate_pure_const (void)
if (pure_const_state == IPA_NEITHER)
break;
}
- if (pure_const_state == IPA_NEITHER)
- break;
/* And finally all loads and stores. */
- for (i = 0; w->iterate_reference (i, ref); i++)
+ for (i = 0; w->iterate_reference (i, ref)
+ && pure_const_state != IPA_NEITHER; i++)
{
enum pure_const_state_e ref_state = IPA_CONST;
bool ref_looping = false;
@@ -1419,7 +1437,8 @@ propagate_pure_const (void)
&& this_state > w_l->state_previously_known)
{
this_state = w_l->state_previously_known;
- this_looping |= w_l->looping_previously_known;
+ if (this_state == IPA_NEITHER)
+ this_looping = w_l->looping_previously_known;
}
if (!this_looping && self_recursive_p (w))
this_looping = true;
