The C++ front end already means to clear DECL_EXTERNAL on callable
functions, we just need to update that for devirtualization.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit a87e57625b130bb9e1fec2130643a4e5d7a3b807
Author: Jason Merrill <ja...@redhat.com>
Date: Tue Aug 19 13:52:25 2014 -0400
PR tree-optimization/62091
* decl2.c (decl_needed_p): Return true for virtual functions when
devirtualizing.
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index de28cb7..63583a8 100644
--- a/gcc/cp/decl2.c
+++ b/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;
diff --git a/gcc/testsuite/g++.dg/ipa/devirt-38.C b/gcc/testsuite/g++.dg/ipa/devirt-38.C
index be8cbdf..2d95bf7 100644
--- a/gcc/testsuite/g++.dg/ipa/devirt-38.C
+++ b/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" } } */
