1 files changed, 55 insertions, 0 deletions
diff --git a/gcc/cp/optimize.cc b/gcc/cp/optimize.cc
index ff4fb5b..7147f5e 100644
--- a/gcc/cp/optimize.cc
+++ b/gcc/cp/optimize.cc
@@ -723,3 +723,58 @@ maybe_clone_body (tree fn)
   /* We don't need to process the original function any further.  */
   return 1;
 }
+
+/* If maybe_clone_body is called while the cdtor is still tentative,
+   DECL_ONE_ONLY will be false and so will be can_alias_cdtor (fn).
+   In that case we wouldn't try to optimize using an alias and instead
+   would emit separate base and complete cdtor.  The following function
+   attempts to still optimize that case when we import_export_decl
+   is called first time on one of the clones.  */
+
+void
+maybe_optimize_cdtor (tree orig_decl)
+{
+  tree fns[3];
+  tree fn = DECL_CLONED_FUNCTION (orig_decl);
+  gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CDTOR_P (fn));
+  if (DECL_INTERFACE_KNOWN (fn)
+      || !TREE_ASM_WRITTEN (fn)
+      || !DECL_ONE_ONLY (orig_decl)
+      || symtab->global_info_ready)
+    return;
+
+  populate_clone_array (fn, fns);
+
+  if (!fns[0] || !fns[1])
+    return;
+  for (int i = 2 - !fns[2]; i >= 0; --i)
+    if (fns[i] != orig_decl && DECL_INTERFACE_KNOWN (fns[i]))
+      return;
+  DECL_INTERFACE_KNOWN (fn) = 1;
+  comdat_linkage (fn);
+  if (!can_alias_cdtor (fn))
+    return;
+  /* For comdat base and complete cdtors put them into the same,
+     *[CD]5* comdat group instead of *[CD][12]*.  */
+  auto n0 = cgraph_node::get_create (fns[0]);
+  auto n1 = cgraph_node::get_create (fns[1]);
+  auto n2 = fns[2] ? cgraph_node::get_create (fns[1]) : NULL;
+  if (n0->lowered || n1->lowered || (n2 && n2->lowered))
+    return;
+  import_export_decl (fns[0]);
+  n1->definition = false;
+  if (!n0->create_same_body_alias (fns[1], fns[0]))
+    return;
+
+  tree comdat_group = cdtor_comdat_group (fns[1], fns[0]);
+  n1 = cgraph_node::get (fns[1]);
+  n0->set_comdat_group (comdat_group);
+  if (n1->same_comdat_group)
+    n1->remove_from_same_comdat_group ();
+  n1->add_to_same_comdat_group (n0);
+  if (fns[2])
+    n2->add_to_same_comdat_group (n0);
+  import_export_decl (fns[1]);
+  /* Remove the body now that it is an alias.  */
+  release_function_body (fns[1]);
+}