re PR tree-optimization/64330 (IPA-ICF merges const exported vars that could be…

re PR tree-optimization/64330 (IPA-ICF merges const exported vars that could be addressable in other TUs)

Fix for PR64330.

	PR tree-optimization/64330
	* ipa-icf.c (sem_variable::parse): Add checking
	for externally visible symbols and do not introduce
	an alias for an external declaration.

From-SVN: r218864

gcc/ChangeLog

+2014-12-18  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/64330
+	* ipa-icf.c (sem_variable::parse): Add checking
+	for externally visible symbols and do not introduce
+	an alias for an external declaration.
+
 2014-12-18  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR bootstrap/63573

gcc/ipa-icf.c

@@ -1139,10 +1139,14 @@ sem_variable::parse (varpool_node *node, bitmap_obstack *stack)
   tree decl = node->decl;
 
   bool readonly = TYPE_P (decl) ? TYPE_READONLY (decl) : TREE_READONLY (decl);
-  bool can_handle = readonly && (DECL_VIRTUAL_P (decl)
-				 || !TREE_ADDRESSABLE (decl));
+  if (!readonly)
+    return NULL;
+
+  bool can_handle = DECL_VIRTUAL_P (decl)
+		    || flag_merge_constants >= 2
+		    || (!TREE_ADDRESSABLE (decl) && !node->externally_visible);
 
-  if (!can_handle)
+  if (!can_handle || DECL_EXTERNAL (decl))
     return NULL;
 
   tree ctor = ctor_for_folding (decl);