re PR tree-optimization/62091 (ice in before_dom_children)

PR tree-optimization/62091
	* decl2.c (decl_needed_p): Return true for virtual functions when
	devirtualizing.

From-SVN: r214181

gcc/cp/ChangeLog

@@ -1,5 +1,9 @@
 2014-08-19  Jason Merrill  <jason@redhat.com>
 
+	PR tree-optimization/62091
+	* decl2.c (decl_needed_p): Return true for virtual functions when
+	devirtualizing.
+
 	PR lto/53808
 	PR c++/61659
 	* decl.c (maybe_commonize_var): Don't use DECL_COMDAT to trigger

gcc/cp/decl2.c

@@ -1975,6 +1975,11 @@ decl_needed_p (tree decl)
   if (flag_keep_inline_dllexport
       && lookup_attribute ("dllexport", DECL_ATTRIBUTES (decl)))
     return true;
+  /* Virtual functions might be needed for devirtualization.  */
+  if (flag_devirtualize
+      && TREE_CODE (decl) == FUNCTION_DECL
+      && DECL_VIRTUAL_P (decl))
+    return true;
   /* Otherwise, DECL does not need to be emitted -- yet.  A subsequent
      reference to DECL might cause it to be emitted later.  */
   return false;

gcc/testsuite/g++.dg/ipa/devirt-38.C

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2"  } */
+/* { dg-options "-O2 -fdump-tree-ccp1"  } */
 class SnmpSyntax
 {
 public:
@@ -27,4 +27,5 @@ void fn1 ()
         c.m_fn1 ();
       }
 }
-// Devirtualization to A::m_fn1 would be possible, but we can not do it at the moment
+/* { dg-final { scan-tree-dump-not "OBJ_TYPE_REF" "ccp1"  } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */