[Bug c++/34772] [4.3/4.4/4.5/4.6/4.7 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[Bug c++/34772] [4.3/4.4/4.5/4.6/4.7 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

--- Comment #16 from Jason Merrill <jason at gcc dot gnu.org> 2011-05-09 17:34:48 UTC ---
Author: jason
Date: Mon May  9 17:34:44 2011
New Revision: 173582

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173582
Log:
    PR c++/34772
    * decl.c (initialize_local_var): Use DECL_INITIAL for simple
    initialization.

Added:
    trunk/gcc/testsuite/c-c++-common/uninit-D-O0.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-D-O0.c
    trunk/gcc/testsuite/c-c++-common/uninit-D.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-D.c
    trunk/gcc/testsuite/c-c++-common/uninit-E-O0.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-E-O0.c
    trunk/gcc/testsuite/c-c++-common/uninit-E.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-E.c
    trunk/gcc/testsuite/c-c++-common/uninit-F-O0.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-F-O0.c
    trunk/gcc/testsuite/c-c++-common/uninit-F.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-F.c
    trunk/gcc/testsuite/c-c++-common/uninit-G-O0.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-G-O0.c
    trunk/gcc/testsuite/c-c++-common/uninit-G.c
      - copied, changed from r173581, trunk/gcc/testsuite/gcc.dg/uninit-G.c
Removed:
    trunk/gcc/testsuite/gcc.dg/uninit-D-O0.c
    trunk/gcc/testsuite/gcc.dg/uninit-D.c
    trunk/gcc/testsuite/gcc.dg/uninit-E-O0.c
    trunk/gcc/testsuite/gcc.dg/uninit-E.c
    trunk/gcc/testsuite/gcc.dg/uninit-F-O0.c
    trunk/gcc/testsuite/gcc.dg/uninit-F.c
    trunk/gcc/testsuite/gcc.dg/uninit-G-O0.c
    trunk/gcc/testsuite/gcc.dg/uninit-G.c
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/34772] [4.3/4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org
      Known to work|                            |4.7.0
            Summary|[4.3/4.4/4.5/4.6/4.7        |[4.3/4.4/4.5/4.6
                   |Regression]                 |Regression]
                   |self-initialisation does    |self-initialisation does
                   |not silence uninitialised   |not silence uninitialised
                   |warnings (-Winit-self       |warnings (-Winit-self
                   |ignored)                    |ignored)
      Known to fail|                            |

--- Comment #17 from Jason Merrill <jason at gcc dot gnu.org> 2011-05-09 20:48:47 UTC ---
Fixed on trunk so far.

[Bug c++/34772] [4.3/4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.6                       |4.4.7

--- Comment #18 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-27 12:12:54 UTC ---
4.3 branch is being closed, moving to 4.4.7 target.

[Bug c++/34772] [4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

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

--- Comment #19 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2011-06-27 13:10:08 UTC ---
I think no one is going to backport this, specially because it produces new
warnings, and users wouldn't like that in a minor version. Let's close it.

[Bug c++/34772] [4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[davi.arnaut at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

--- Comment #20 from Davi Arnaut <davi.arnaut at oracle dot com> 2011-06-27 16:40:52 UTC ---
Actually, we would really like it. Currently, we have to disable it because
most of the warnings are bogus. New _valid_ warnings are welcome.

[Bug c++/34772] [4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

--- Comment #21 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2011-06-27 18:01:40 UTC ---
(In reply to comment #20)
> Actually, we would really like it. Currently, we have to disable it because
> most of the warnings are bogus. New _valid_ warnings are welcome.

If you think most -Winit-self warnings are bogus, this fix cannot help you.

[Bug c++/34772] [4.4/4.5/4.6 Regression] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)

[davi.arnaut at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772

--- Comment #22 from Davi Arnaut <davi.arnaut at oracle dot com> 2011-06-27 19:15:45 UTC ---
(In reply to comment #21)
>> Actually, we would really like it. Currently, we have to disable it because
>> most of the warnings are bogus. New _valid_ warnings are welcome.
>
> If you think most -Winit-self warnings are bogus, this fix cannot help you.

Sorry, I wasn't talking about -Winit-self warnings. I meant that most
uninitialised warnings in C++ are bogus [1]. Hence, we have to work around this
by actually initializing certain variables. By initializing the variable we
lose coverage by tools such as valgrind,. The self-initialization trick allow
us to avoid this problem.

Also, we even had a runtime "performance issue" associated with it in debug
builds. A large structure (containing floats, etc) needed to be partially
initialized to silence the warnings, but it caused a penalty since it was
located in a hot function (ended up slowing our test suite).

Anyway, point is, it would be nice to have this fixed in the early 4.x
branches.

1. I believe there is a bug report about this.