Do not dissolve comdat groups in inliner

Do not dissolve comdat groups in inliner

[Jan Hubicka]

Hi,
in the testcase bellow the comdat local function is inlined and inliner mistakely
dissolve the whole comdat group.  This is wrong and leads to ICE here, but it also
may lead to undefined symbols due to groups being wrong.

Bootstrapped/regtested x86_64-linux, comitted.

	PR ipa/64988
	* ipa-inline-transform.c (clone_inlined_nodes): Do not dissolve
	comdat groups.
	* g++.dg/torture/pr64988.C: New testcase.
Index: ipa-inline-transform.c
===================================================================
--- ipa-inline-transform.c	(revision 221122)
+++ ipa-inline-transform.c	(working copy)
@@ -213,7 +213,7 @@ clone_inlined_nodes (struct cgraph_edge
 	     For now we keep the ohter functions in the group in program until
 	     cgraph_remove_unreachable_functions gets rid of them.  */
 	  gcc_assert (!e->callee->global.inlined_to);
-	  e->callee->dissolve_same_comdat_group_list ();
+	  e->callee->remove_from_same_comdat_group ();
 	  if (e->callee->definition
 	      && inline_account_function_p (e->callee))
 	    {
@@ -243,7 +243,7 @@ clone_inlined_nodes (struct cgraph_edge
 	}
     }
   else
-    e->callee->dissolve_same_comdat_group_list ();
+    e->callee->remove_from_same_comdat_group ();
 
   e->callee->global.inlined_to = inlining_into;
 
Index: testsuite/g++.dg/torture/pr64988.C
===================================================================
--- testsuite/g++.dg/torture/pr64988.C	(revision 0)
+++ testsuite/g++.dg/torture/pr64988.C	(revision 0)
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-options "-O -fdeclone-ctor-dtor" }
+struct A {
+  virtual ~ A ();
+};
+
+struct B : virtual A {};
+struct C : virtual A {};
+
+struct D : B, C {};
+
+D d;