[Bug fortran/13490] New: Compiler rejects valid constant -2147483648 for 32-bit int

[Bug fortran/13490] New: Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

The attached program compiles and runs correctly with Intel Fortran 95 8.0 and
Lahey Fortran 95 6.1, but generates an error with gfortran. The error is:

In file parambug.f90:5
 
    integer(MY_KIND), parameter :: X = -2147483648
                                             1
Error: Arithmetic overflow at (1)

-- 
           Summary: Compiler rejects valid constant -2147483648 for 32-bit
                    int
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: coyote at coyotegulch dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux
  GCC host triplet: i686-pc-linux
GCC target triplet: i686-pc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

------- Additional Comments From coyote at coyotegulch dot com  2003-12-25 17:52 -------
Created an attachment (id=5370)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5370&action=view)
An example the gfortran can't compile


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] [gfortran] Compiler rejects valid constant -2147483648 for 32-bit int

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-12-25 17:54 -------
Most likely what is happening is also happens in C that 2147483648 has to defined as an unsigned 
and then the negative is applied causing this error.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
            Summary|Compiler rejects valid      |[gfortran] Compiler rejects
                   |constant -2147483648 for 32-|valid constant -2147483648
                   |bit int                     |for 32-bit int
   Target Milestone|---                         |tree-ssa


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] [gfortran] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

------- Additional Comments From coyote at coyotegulch dot com  2003-12-25 19:13 -------
Fortran 95 uses GMP internally, while (as far as I know), the C compiler does
not. The following is a message I posted to the GNU Fortran 95 mailing list a
few minutes ago:

I reported the following as a bug, but after reading the gfortran source
code, I'm not entirely certain of my diagnosis.

This program compiles and exceutes with Lahey and Intel compilers, but
*not* with gfortran:

    program parambug
    implicit none

    integer, parameter :: MY_KIND  = SELECTED_INT_KIND(10)
    integer(MY_KIND), parameter :: X = -2147483648

    write (*,*) X

    end program parambug

The result of compiling with gfortran is:

     In file parambug.f90:5

    integer(MY_KIND), parameter :: X = -2147483648
                                             1
    Error: Arithmetic overflow at (1)

Looking at arith.c, I find this comment:

      mpz_init (int_info->min_int);
      mpz_neg (int_info->min_int, int_info->huge);
      /* No -1 here, because the representation is symmetric.  */


Yet I can't find anything in the Fortran 95 standard that supports the
contention that potitive and negative values are symmetric (as suggested
by the comment.

So is this a bug or not? It certainly is different from other Fortran 95
compilers... 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] [gfortran] Compiler rejects valid constant -2147483648 for 32-bit int

[pbrook at gcc dot gnu dot org]

------- Additional Comments From pbrook at gcc dot gnu dot org  2003-12-26 15:25 -------
See 
http://gcc.gnu.org/ml/fortran/2003-12/msg00082.html 
Relevant section of (draft) F95 standard is 13.7.1 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-12-26 15:25:51
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] [gfortran] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

------- Additional Comments From coyote at coyotegulch dot com  2003-12-26 19:01 -------
gfortran is behaving correctly according to the Standard.

In reflection of interoperability needs, I've posted a patch to pcc-patches that
implements a new flag, -fasymmetrical-integers. This flag tells gfortran to
accept integers in the range [-n-1,n], whereas the standard requires the range
[-n,n].

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] [gfortran] Compiler rejects valid constant -2147483648 for 32-bit int

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.5.0                       |---


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-07-13 16:23 -------
*** Bug 16512 has been marked as a duplicate of this bug. ***

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

------- Additional Comments From coyote at coyotegulch dot com  2004-10-19 18:49 -------
Posted a slightly revised patch, ten months after the first.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-19 19:15 -------
Patch here: <http://gcc.gnu.org/ml/gcc-patches/2004-10/msg01613.html>.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1123 bytes --]


------- Additional Comments From coyote at coyotegulch dot com  2004-10-22 00:05 -------
When this topic came up last year, I was in favor of gfortran working like other
Fortran 95 compilers, which accept minimum integer values of -(2**(n-1)).
Several Fortran language lawyers insisted that the default behavior should be to
reject such values, as they are not symmetrical across ABS() (a requirement
implied by the Standard.)

My previous patches for this problem have catered to the language lawyers by
adding a switch to enable "asymmetric" integers. I never liked doing it that way.

After a discussion with Tobias Schlüter, I've decided to present the following
patch, which causes gfortran to behave exactly like other Fortran 95 compilers.
For a -pedantic compile, gfortran will now display a warning about a potential
Standard violation.

This patch gives me warm fuzzies. The gods only know what the language lawyers
will think... :)

Bootstrapped and tested on i686-pc-linux and x86_64-pc-linux.

http://gcc.gnu.org/ml/gcc-patches/2004-10/msg01876.html

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[coyote at coyotegulch dot com]

------- Additional Comments From coyote at coyotegulch dot com  2004-10-28 21:45 -------
Patch committed after approval

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-28 22:25 -------
Subject: Bug 13490

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	srladd@gcc.gnu.org	2004-10-28 22:25:18

Modified files:
	gcc/fortran    : ChangeLog 

Log message:
	Fix for PR fortran/13490, PR fortran/17912

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fortran/ChangeLog.diff?cvsroot=gcc&r1=1.239&r2=1.240



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490

[Bug fortran/13490] Compiler rejects valid constant -2147483648 for 32-bit int

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-29 04:41 -------
Subject: Bug 13490

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	billingd@gcc.gnu.org	2004-10-29 04:41:49

Modified files:
	gcc/testsuite  : ChangeLog 
	gcc/testsuite/gfortran.dg/g77: 20030326-1.f README 

Log message:
	2004-10-29  David Billinghurst <David.Billinghurst@riotinto.com>
	
	PR fortran/13490
	* gfortran.dg/g77/20030326-1.f: Change xfail on error to warning.
	* gfortran.dg/g77/README: Update.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.4516&r2=1.4517
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/g77/20030326-1.f.diff?cvsroot=gcc&r1=1.1&r2=1.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/g77/README.diff?cvsroot=gcc&r1=1.6&r2=1.7



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13490