[Bug c++/60854] New: inline constructor of extern template

[Bug c++/60854] New: inline constructor of extern template

[joachim.schoeberl at tuwien dot ac.at]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

            Bug ID: 60854
           Summary: inline constructor of extern template
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: joachim.schoeberl at tuwien dot ac.at

Created attachment 32610
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32610&action=edit
source file

this code was accepted by gcc-4.8 up to (at least) gcc-4.9-20140323, but g++
(GCC) 4.9.0 20140411 (prerelease) complains.

compiled with
g++ -c -O2 --std=c++11 test.cpp



error message of gcc-4.9.0 prerelease:

test.cpp: In function ‘void Func()’:
test.cpp:5:46: error: inlining failed in call to always_inline
‘MyClass<T>::MyClass() [with T = double]’: function body not available
   __attribute__ ((__always_inline__)) inline MyClass () { ; }
                                              ^
test.cpp:12:19: error: called from here
   MyClass<double> x;
                   ^
>From gcc-bugs-return-449117-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Apr 15 21:32:16 2014
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From: "bernd.edlinger at hotmail dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug bootstrap/60830] [4.9 Regression] ICE on bootstrapping on cygwin
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`830

Bernd Edlinger <bernd.edlinger at hotmail dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bernd.edlinger at hotmail dot de

--- Comment #23 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
FYI: I have 32-bit cygwin 1.7.28-2/XP SP2 here, and the following configuration
builds successfully:

../gcc-4.9.0-RC-20140411/configure --prefix=/<full-path-to-install>
--enable-languages=c,c++

gmp etc. in-tree with: contrib/download_prerequisites

[Bug ipa/60854] [4.9/4.10 Regression] inline constructor of extern template

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-04-16
                 CC|                            |hubicka at gcc dot gnu.org
          Component|c++                         |ipa
   Target Milestone|---                         |4.9.1
            Summary|inline constructor of       |[4.9/4.10 Regression]
                   |extern template             |inline constructor of
                   |                            |extern template
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Not sure how the C++ 'extern template' explicit instantiation interacts with
the GCC always-inline extension.  But with always-inline it is an _error_
to have a function not inlined and thus we omit the body of the function.

Somehow early inlining doesn't see that MyClass::MyClass is always-inline,
this works in 4.8 and the constructor is always-inlined.

Honza?

[Bug ipa/60854] [4.9/4.10 Regression] inline constructor of extern template

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

--- Comment #3 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
OK, the problem is that we see the reference to alias and decide to keep the
alias for future inlining. But when processing the refernce from alias to
function itself, we throw it away. We need to keep the body, too ;)

(the existing node->alias check actually cares about oposite case where we want
to keep weakrefs)

Index: ipa.c
===================================================================
--- ipa.c       (revision 209435)
+++ ipa.c       (working copy)
@@ -138,7 +138,7 @@ process_references (struct ipa_ref_list
       symtab_node *node = ref->referred;

       if (node->definition && !node->in_other_partition
-         && ((!DECL_EXTERNAL (node->decl) || node->alias)
+         && ((!DECL_EXTERNAL (node->decl) || node->alias || ref->use ==
IPA_REF_ALIAS)
              || (((before_inlining_p
                    && (cgraph_state < CGRAPH_STATE_IPA_SSA
                        || !lookup_attribute ("always_inline",

[Bug ipa/60854] [4.9/4.10 Regression] inline constructor of extern template

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

--- Comment #4 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Author: hubicka
Date: Thu Apr 17 02:22:57 2014
New Revision: 209459

URL: http://gcc.gnu.org/viewcvs?rev=209459&root=gcc&view=rev
Log:

    PR ipa/60854
    * ipa.c (symtab_remove_unreachable_nodes): Mark targets of
    external aliases alive, too.
    * g++.dg/torture/pr60854.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/torture/pr60854.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/ipa.c
    trunk/gcc/testsuite/ChangeLog

[Bug ipa/60854] [4.9 Regression] inline constructor of extern template

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.10.0
            Summary|[4.9/4.10 Regression]       |[4.9 Regression] inline
                   |inline constructor of       |constructor of extern
                   |extern template             |template
      Known to fail|                            |4.9.0

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug ipa/60854] [4.9 Regression] inline constructor of extern template

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

--- Comment #6 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Author: hubicka
Date: Sat May 17 22:18:25 2014
New Revision: 210563

URL: http://gcc.gnu.org/viewcvs?rev=210563&root=gcc&view=rev
Log:

    PR ipa/60854
    * ipa.c (symtab_remove_unreachable_nodes): Mark targets of
    external aliases alive, too.
    * g++.dg/torture/pr60854.C: New testcase.

Added:
    branches/gcc-4_9-branch/gcc/testsuite/g++.dg/torture/pr60854.C
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/ipa.c
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog

[Bug ipa/60854] [4.9 Regression] inline constructor of extern template

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60854

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.