[PATCH] Fix same_comdat_group handling in cgraph_remove_unreachable_nodes (PR c++/42386)

[Jakub Jelinek]

Hi!

We shouldn't consider same_comdat_group links to make nodes reachable for
DECL_EXTERNAL nodes - for those whether they are in the same comdat group or
not doesn't matter.

Bootstrapped/regtested on x86_64-linux.  Ok for trunk?

2009-12-16  Jakub Jelinek  <jakub@redhat.com>

	PR c++/42386
	* ipa.c (cgraph_remove_unreachable_nodes): Don't mark
	same_comdat_group nodes as reachable if DECL_EXTERNAL.

	* g++.dg/opt/dtor3.C: New test.

--- gcc/ipa.c.jj	2009-12-10 22:56:22.000000000 +0100
+++ gcc/ipa.c	2009-12-16 18:26:00.000000000 +0100
@@ -185,6 +185,7 @@ cgraph_remove_unreachable_nodes (bool be
 	 also reachable.  */
       if (node->same_comdat_group
 	  && node->reachable
+	  && !DECL_EXTERNAL (node->decl)
 	  && !node->global.inlined_to)
 	{
 	  for (next = node->same_comdat_group;
--- gcc/testsuite/g++.dg/opt/dtor3.C.jj	2009-12-16 18:08:11.000000000 +0100
+++ gcc/testsuite/g++.dg/opt/dtor3.C	2009-12-16 18:06:36.000000000 +0100
@@ -0,0 +1,11 @@
+// PR c++/42386
+// { dg-do compile }
+// { dg-options "-O2" }
+# 1 "A.h" 1
+#pragma interface
+struct D { virtual bool d () const; };
+struct E { virtual ~E (); virtual void *e () const = 0; };
+struct A : public D, public E { ~A () {} };
+# 5 "F.h" 1
+struct F : public A { void *f () const; void *e () const; };
+void *F::e () const { return __null; }

	Jakub