[Bug fortran/58410] New: Bogus uninitialized variable warning for allocatable derived type array function result

[Bug fortran/58410] New: Bogus uninitialized variable warning for allocatable derived type array function result

[vladimir.fuka at gmail dot com]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

            Bug ID: 58410
           Summary: Bogus uninitialized variable warning for allocatable
                    derived type array function result
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vladimir.fuka at gmail dot com

gfortran  -c -Wall -O2 uninit.f90 
uninit.f90: In function ‘sub’:
uninit.f90:22:0: warning: ‘new.dim[0].ubound’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
         new = fun()
 ^


gfortran  -c -Wall -O1 uninit.f90
without warning




gfortran  -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/usr/local/gcc-4.8/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.8-20130509/configure --enable-languages=c,c++,fortran
--with-cloog --prefix=/usr/local/gcc-4.8
Thread model: posix
gcc version 4.8.1 20130509 (prerelease) (GCC)
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From: "vladimir.fuka at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/58410] Bogus uninitialized variable warning for allocatable derived type array function result
Date: Fri, 13 Sep 2013 08:48:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idX410

--- Comment #1 from Vladimir Fuka <vladimir.fuka at gmail dot com> ---
Created attachment 30815
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id0815&actioníit
uninit.f90

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-09-15
                 CC|                            |janus at gcc dot gnu.org
            Summary|Bogus uninitialized         |[4.8/4.9 Regression] Bogus
                   |variable warning for        |uninitialized variable
                   |allocatable derived type    |warning for allocatable
                   |array function result       |derived type array function
                   |                            |result
     Ever confirmed|0                           |1

--- Comment #2 from janus at gcc dot gnu.org ---
Confirmed with 4.8 and trunk. The bogus warning does not seem to appear with
4.7.3.

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

--- Comment #3 from janus at gcc dot gnu.org ---
Slightly reduced test case:


module m
  implicit none

  type series
    real,allocatable :: a(:)
  end type

  contains

    function fun()
      type(series),allocatable :: fun(:)
      allocate(fun(0))
    end function

    subroutine sub
      type(series),allocatable :: new(:)
      integer :: j
      do j=1,2
        new = fun()
      end do
    end subroutine

end module

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.8.3

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

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

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

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

Paul Thomas <pault at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P3
                 CC|                            |pault at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |pault at gcc dot gnu.org

--- Comment #4 from Paul Thomas <pault at gcc dot gnu.org> ---
This is not a serious regression and so I have set it to P3.

That said, it is a real bug and I am just now regtesting the fix.

Assigning myself.

Paul

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

--- Comment #6 from Paul Thomas <pault at gcc dot gnu.org> ---
Author: pault
Date: Sun Jan 19 18:04:22 2014
New Revision: 206778

URL: http://gcc.gnu.org/viewcvs?rev=206778&root=gcc&view=rev
Log:
2014-01-19  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/58410
    * trans-array.c (gfc_alloc_allocatable_for_assignment): Do not
    use the array bounds of an unallocated array but set its size
    to zero instead.

Modified:
    branches/gcc-4_8-branch/gcc/fortran/ChangeLog
    branches/gcc-4_8-branch/gcc/fortran/trans-array.c

[Bug fortran/58410] [4.8/4.9 Regression] Bogus uninitialized variable warning for allocatable derived type array function result

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58410

Paul Thomas <pault at gcc dot gnu.org> changed:

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

--- Comment #7 from Paul Thomas <pault at gcc dot gnu.org> ---
Fixed on trunk and 4.8.

Thanks for the report

Paul