https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61602
--- Comment #8 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
OK, the problem is that the variable becomes unreachable after other variable
is declared writeonly and its constructor is killed. I am testing:
Index: ipa.c
===================================================================
--- ipa.c (revision 218730)
+++ ipa.c (working copy)
@@ -714,14 +714,18 @@ set_readonly_bit (varpool_node *vnode, v
/* Set writeonly bit and clear the initalizer, since it will not be needed.
*/
bool
-set_writeonly_bit (varpool_node *vnode, void *data ATTRIBUTE_UNUSED)
+set_writeonly_bit (varpool_node *vnode, void *data)
{
vnode->writeonly = true;
if (optimize)
{
DECL_INITIAL (vnode->decl) = NULL;
if (!vnode->alias)
- vnode->remove_all_references ();
+ {
+ if (vnode->num_references ())
+ *(bool *)data = true;
+ vnode->remove_all_references ();
+ }
}
return false;
}
@@ -739,15 +743,18 @@ clear_addressable_bit (varpool_node *vno
/* Discover variables that have no longer address taken or that are read only
and update their flags.
+ Return true when unreachable symbol removan should be done.
+
FIXME: This can not be done in between gimplify and omp_expand since
readonly flag plays role on what is shared and what is not. Currently we
do
this transformation as part of whole program visibility and re-do at
ipa-reference pass (to take into account clonning), but it would
make sense to do it before early optimizations. */
-void
+bool
ipa_discover_readonly_nonaddressable_vars (void)
{
+ bool remove_p = false;
varpool_node *vnode;
if (dump_file)
fprintf (dump_file, "Clearing variable flags:");
@@ -762,14 +769,16 @@ ipa_discover_readonly_nonaddressable_var
bool read = false;
bool explicit_refs = true;
- process_references (vnode, &written, &address_taken, &read,
&explicit_refs);
+ process_references (vnode, &written, &address_taken, &read,
+ &explicit_refs);
if (!explicit_refs)
continue;
if (!address_taken)
{
if (TREE_ADDRESSABLE (vnode->decl) && dump_file)
fprintf (dump_file, " %s (non-addressable)", vnode->name ());
- vnode->call_for_node_and_aliases (clear_addressable_bit, NULL,
true);
+ vnode->call_for_node_and_aliases (clear_addressable_bit, NULL,
+ true);
}
if (!address_taken && !written
/* Making variable in explicit section readonly can cause section
@@ -785,11 +794,13 @@ ipa_discover_readonly_nonaddressable_var
{
if (dump_file)
fprintf (dump_file, " %s (write-only)", vnode->name ());
- vnode->call_for_node_and_aliases (set_writeonly_bit, NULL, true);
+ vnode->call_for_node_and_aliases (set_writeonly_bit, &remove_p,
+ true);
}
}
if (dump_file)
fprintf (dump_file, "\n");
+ return remove_p;
}
/* Free inline summary. */
Index: cgraph.h
===================================================================
--- cgraph.h (revision 218726)
+++ cgraph.h (working copy)
@@ -2188,7 +2188,7 @@ void record_references_in_initializer (t
/* In ipa.c */
void cgraph_build_static_cdtor (char which, tree body, int priority);
-void ipa_discover_readonly_nonaddressable_vars (void);
+bool ipa_discover_readonly_nonaddressable_vars (void);
/* In varpool.c */
tree ctor_for_folding (tree);
Index: testsuite/gcc.dg/torture/pr61602.c
===================================================================
--- testsuite/gcc.dg/torture/pr61602.c (revision 0)
+++ testsuite/gcc.dg/torture/pr61602.c (revision 0)
@@ -0,0 +1,8 @@
+int a;
+int *b = &a, **c = &b;
+int
+main ()
+{
+ int **d = &b;
+ *d = 0;
+}
Index: ipa-reference.c
===================================================================
--- ipa-reference.c (revision 218726)
+++ ipa-reference.c (working copy)
@@ -676,11 +676,12 @@ propagate (void)
XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
int order_pos;
int i;
+ bool remove_p;
if (dump_file)
cgraph_node::dump_cgraph (dump_file);
- ipa_discover_readonly_nonaddressable_vars ();
+ remove_p = ipa_discover_readonly_nonaddressable_vars ();
generate_summary ();
/* Propagate the local information through the call graph to produce
@@ -867,7 +868,7 @@ propagate (void)
if (dump_file)
splay_tree_delete (reference_vars_to_consider);
reference_vars_to_consider = NULL;
- return 0;
+ return remove_p ? TODO_remove_functions : 0;
}
/* Return true if we need to write summary of NODE. */
