[Bug middle-end/50040] New: [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[Bug middle-end/50040] New: [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[jan.kratochvil at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

             Bug #: 50040
           Summary: [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used
                    uninitialized in this function
    Classification: Unclassified
           Product: gcc
           Version: 4.5.4
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jan.kratochvil@redhat.com
            Target: x86_64-unknown-linux-gnu


PASS: gcc (GCC) 4.4.7 20110810 (prerelease)
FAIL: gcc (GCC) 4.5.4 20110810 (prerelease)
FAIL: gcc (GCC) 4.6.2 20110810 (prerelease)
FAIL: gcc (GCC) 4.7.0 20110810 (experimental)

int *p;
void f (void)
{
  struct { int y; } x;
  *p = x.y;
}
--------------------------------------------------------------------------------
-c -Wall -O2
--------------------------------------------------------------------------------
PASS:
1.c: In function ‘f’:
1.c:5: warning: ‘x.y’ is used uninitialized in this function
FAIL:
<nothing>

[Bug middle-end/50040] [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-11 10:04:06 UTC ---
We should have never accepted the aggregate warning code in 4.4 and earlier
in it's current awkward form that only works for "testcases".  It was removed.

This is a dup of PR????.

[Bug middle-end/50040] [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[jan.kratochvil at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #2 from Jan Kratochvil <jan.kratochvil at redhat dot com> 2011-08-11 10:41:30 UTC ---
I was searching for duplicates but I haven't found a close enough one without
knowing GCC internals.

[Bug middle-end/50040] [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-08-11
         AssignedTo|unassigned at gcc dot       |rguenth at gcc dot gnu.org
                   |gnu.org                     |
   Target Milestone|---                         |4.5.4
     Ever Confirmed|0                           |1

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-11 10:58:07 UTC ---
I have a patch to restore the warning for this toy testcase.

[Bug middle-end/50040] [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[jan.kratochvil at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #4 from Jan Kratochvil <jan.kratochvil at redhat dot com> 2011-08-11 11:22:41 UTC ---
Thanks for a fix, FYI this is a reduced real world problem.
During backporting of
  [patch] Implement core file's PID for s390* and ppc*
  http://sourceware.org/ml/binutils/2011-04/msg00272.html
specifically misordered:
vvv    elf_tdata (abfd)->core_pid = psinfo.pr_pid;
^^^    memcpy (&psinfo, note->descdata, sizeof (psinfo));
I got a warning from RHEL-6 gcc-4.4.5-6.el6.x86_64 which I did not get the
warning during the patch preparation on Fedora 14 gcc-4.5.1-4.fc14.x86_64.
This problem was found and would be found afterwards anyway by a testcase but
not every line of GCC compiled code has a testcase.

[Bug middle-end/50040] [4.5/4.6/4.7 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-11 14:28:39 UTC ---
Author: rguenth
Date: Thu Aug 11 14:28:36 2011
New Revision: 177667

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=177667
Log:
2011-08-11  Richard Guenther  <rguenther@suse.de>

    PR middle-end/50040
    * gimplify.c (gimplify_modify_expr_complex_part): Mark the
    load of the other piece with TREE_NO_WARNING.
    * tree-flow.h (warn_uninit): Adjust prototype.
    * tree-ssa.c (warn_uninit): Take uninitialized SSA name,
    the base variable and the expression that is used separately.
    Properly query all TREE_NO_WARNING flags.
    (struct walk_data): Remove.
    (warn_uninitialized_var): Likewise.
    (warn_uninitialized_vars): Do not walk gimple pieces but simply
    look at all SSA uses of the statement.  Handle unused memory
    separately.
    * tree-ssa-uninit.c (warn_uninitialized_phi): Adjust.

    * g++.dg/warn/unit-1.C: Un-XFAIL.
    * gcc.dg/uninit-I.c: Likewise.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimplify.c
    trunk/gcc/testsuite/g++.dg/warn/unit-1.C
    trunk/gcc/testsuite/gcc.dg/uninit-I.c
    trunk/gcc/tree-flow.h
    trunk/gcc/tree-ssa-uninit.c
    trunk/gcc/tree-ssa.c

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.7.0
            Summary|[4.5/4.6/4.7 Regression]    |[4.5/4.6 Regression] missed
                   |missed warning: ‘x.y’ is    |warning: ‘x.y’ is used
                   |used uninitialized in this  |uninitialized in this
                   |function                    |function

--- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-11 14:28:59 UTC ---
Fixed for 4.7 sofar.

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sezeroz at gmail dot com

--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-11-02 09:49:45 UTC ---
*** Bug 50950 has been marked as a duplicate of this bug. ***

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #8 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-11-03 15:14:38 UTC ---
Patch doesn't apply to the 4.6 branch.  Don't hold your breath.

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |belyshev at depni dot
                   |                            |sinp.msu.ru

--- Comment #9 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-03 13:28:07 UTC ---
*** Bug 50966 has been marked as a duplicate of this bug. ***

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #10 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-03 13:29:56 UTC ---
It's also questionable to cause new warnings to appear on the branch if
you consider code using -Werror.  Leaving open a bit for further consideration,
should be closed as fixed for 4.7 once that is released and it didn't make
the 4.6 branch.

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |szo at szo dot hu

--- Comment #11 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-03 15:16:57 UTC ---
*** Bug 51740 has been marked as a duplicate of this bug. ***

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[sezeroz at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

--- Comment #12 from Ozkan Sezer <sezeroz at gmail dot com> 2012-01-03 16:54:00 UTC ---
(In reply to comment #10)
> It's also questionable to cause new warnings to appear on the branch if
> you consider code using -Werror.

gcc-4.4 used to warn (see bug 50950), therefore if someone's build is using
-Werror and added such uninitialized vars to his code _after_ beginning to use
gcc >= 4.5, he is not getting the error despite the fact that he wants to.

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug middle-end/50040] [4.5/4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.5.4                       |4.6.4

--- Comment #13 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-02 11:38:52 UTC ---
The 4.5 branch is being closed, adjusting target milestone.

[Bug middle-end/50040] [4.6 Regression] missed warning: ‘x.y’ is used uninitialized in this function

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50040

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.6.4                       |4.7.0

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-12 16:17:46 UTC ---
The 4.6 branch has been closed, fixed in GCC 4.7.0.