[Bug fortran/32035] New: '<anonymous>' may be used uninitialized in this function

[Bug fortran/32035] New: '<anonymous>' may be used uninitialized in this function

[P dot Schaffnit at access dot rwth-aachen dot de]

Hi!

This a very minor thing, but it turns out to be a bit annoying: gfortran now
and then (rather randomly in my opinion) throws this compilation diagnostic, of
which I don't seem to make head or tail:
warning: '<anonymous>' may be used uninitialized in this function

This warning looks quite meaningless to me (at best).

Cheers!

Philippe

PS: gfortran -O1 -g -Wall -c Source.f90
Source.f90: In function 'test':
Source.f90:35: warning: '<anonymous>' may be used uninitialized in this
function

PPS: don't look for much sense, I just tried to cut down some valid sources
while keeping this behaviour...

!
      SUBROUTINE Test
!
      IMPLICIT   NONE
!
      LOGICAL ::   Logical_1
!
      INTEGER :: Integer_1
      INTEGER :: Integer_2
      INTEGER :: Integer_3
      INTEGER :: Integer_4
      INTEGER, PARAMETER :: Dft = 4
      INTEGER, PARAMETER :: Parameter_1 = 1, Parameter_2 = 2
!
      CHARACTER ( LEN = 30 ) ::   String_1
!
      READ ( 5, * ) String_1
!
      Integer_3  = Parameter_1
      Integer_4 = 666
!
      SELECT CASE ( TRIM(String_1) )
      CASE ( "A" )
        Integer_3  = Parameter_1
      CASE ( "B" )
        Integer_3  = Parameter_2
      CASE DEFAULT
        STOP
      END SELECT
!
      IF ( Integer_3 .EQ. Parameter_2 ) THEN
!
        READ ( 5, * ) Integer_1
!
        Integer_2 = 0
        DO Integer_4 = 1, Integer_1
!
          READ ( 5, * ) String_1
          SELECT CASE ( TRIM(String_1) )
          CASE ( "C" )
            Logical_1 = .TRUE.
          CASE ( "D" )
            Logical_1 = .FALSE.
          CASE DEFAULT
            STOP
          END SELECT
!
        ENDDO
      ENDIF
!
      RETURN
      END SUBROUTINE Test
!


PPPS:
gfortran -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /USER/philippe/Irix/Gcc_Sources/configure
--prefix=/usr1/MICRESS/Philippe/Tools/Gcc --enable-languages=c,fortran
--disable-maintainer-mode --disable-shared
--with-mpfr=/usr1/MICRESS/Philippe/Tools/Mpfr
--with-gmp=/usr1/MICRESS/Philippe/Tools/Gmp --with-htmldir
Thread model: posix
gcc version 4.3.0 20070522 (experimental)


-- 
           Summary: '<anonymous>' may be used uninitialized in this function
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: P dot Schaffnit at access dot rwth-aachen dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug middle-end/32035] '<anonymous>' may be used uninitialized in this function

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2007-05-22 11:15 -------
The error message comes from the middle-end and the variable name is Integer_1,
line 33 is:

        READ ( 5, * ) Integer_1

There are two problems: First, why has the variable no name for the middle end;
secondly, why does the middle end print this warning for the following call:

        _gfortran_st_read (&dt_parm.5);
        _gfortran_transfer_integer (&dt_parm.5, &integer_1, 4);
        _gfortran_st_read_done (&dt_parm.5);


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
          Component|fortran                     |middle-end
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-05-22 11:15:35
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2007-05-22 16:31 -------
> why has the variable no name for the middle end;
that is a front issue for now, it might not be complaining about Integer_1 but
a different variable.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
          Component|middle-end                  |fortran


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[burnus at gcc dot gnu dot org]

------- Comment #3 from burnus at gcc dot gnu dot org  2007-05-22 18:29 -------
> > why has the variable no name for the middle end;
> that is a front issue for now

Hmm, why did this trick to get rid of PRs not work? ;-)

Reduced test case:

      subroutine Test
      implicit none
      integer,volatile :: Integer_1
      integer          :: Integer_4
      character(len=3) :: String_1
      String_1 = '124'
      select case(String_1)
        case default
          stop
      end select
      Integer_1 = 3
      do Integer_4 = 1, Integer_1
        String_1 = '098'
        select case(String_1)
          case default
            stop
        end select
      end do
      end subroutine Test

Gives two bogus warnings:
  warning: 'integer_4' may be used uninitialized in this function
  warning: '<anonymous>' may be used uninitialized in this function

The integer_4 warning is completely surprising:
  int4 integer_4;
[...]
    integer_4 = 1;
    if (integer_4 <= D.1366)
[...]
              D.1373 = integer_4 == D.1366;
              integer_4 = integer_4 + 1;
I fail to see why it could be seen as undefined.

For <anonymous> I don't see what goes wrong.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2007-05-22 18:32 -------
It might have to do with stop not being marked as noreturn.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[burnus at gcc dot gnu dot org]

------- Comment #5 from burnus at gcc dot gnu dot org  2007-05-22 20:14 -------
> It might have to do with stop not being marked as noreturn.
How to mark as noreturn? I mean differently from what is alreay done in
trans-decl.c:

  gfor_fndecl_stop_numeric =
    gfc_build_library_function_decl (get_identifier (PREFIX("stop_numeric")),
                                     void_type_node, 1, gfc_int4_type_node);
  /* Stop doesn't return.  */
  TREE_THIS_VOLATILE (gfor_fndecl_stop_numeric) = 1;


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2007-05-23 03:18 -------
Ok, what is going on here has to deal with how select/case works for strings.  
What the front-end produces confuses the crazy out of the middle-end and the
middle-end does not know where the jumps can go so it assumes it can go to
either place.  After the first select, the middle thinks it can reach where the
second select is supposed to reach.  So what should happen here is the
front-end respentation of select/case for strings need to be improved.  

Maybe instead of using labels, it can use a constant value and then a normal
switch statement.  This will also improve code gen and less confuse the
middle-end.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[fxcoudert at gcc dot gnu dot org]

-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |fxcoudert at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-05-22 11:15:35         |2007-07-04 07:34:44
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[steven at gcc dot gnu dot org]

------- Comment #7 from steven at gcc dot gnu dot org  2007-07-11 21:42 -------
The proposed patch (http://gcc.gnu.org/ml/gcc-patches/2007-07/msg01098.html)
breaks library compatibility. Is this intentional?


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |steven at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[fxcoudert at gcc dot gnu dot org]

------- Comment #8 from fxcoudert at gcc dot gnu dot org  2007-07-11 21:54 -------
I think it was decided that until 4.3 is released, we don't care about
libgfortran ABI stability
(http://gcc.gnu.org/ml/gcc-patches/2007-07/msg00927.html)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[fxcoudert at gcc dot gnu dot org]

------- Comment #9 from fxcoudert at gcc dot gnu dot org  2007-07-27 14:26 -------
Subject: Bug 32035

Author: fxcoudert
Date: Fri Jul 27 14:26:43 2007
New Revision: 126978

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=126978
Log:
        PR fortran/32035

        * trans-stmt.c (gfc_trans_character_select): Replace the
        mechanism with labels by a SWITCH_EXPR.
        * trans-decl.c (gfc_build_builtin_function_decls): Change
        return type for select_string.

        * runtime/select.c (select_string): Adjust prototype and function
        so that the return value is an integer, not a pointer.

        * gfortran.dg/select_char_1.f90: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/select_char_1.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/trans-decl.c
    trunk/gcc/fortran/trans-stmt.c
    trunk/gcc/testsuite/ChangeLog
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/runtime/select.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035

[Bug fortran/32035] '<anonymous>' may be used uninitialized in this function

[fxcoudert at gcc dot gnu dot org]

------- Comment #10 from fxcoudert at gcc dot gnu dot org  2007-07-27 14:28 -------
Fixed on mainline.


-- 

fxcoudert at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32035