[Bug fortran/23138] New: real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[Bug fortran/23138] New: real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[post at tillmann-wegst dot de]

Hi all, 

I'd like to report what looks like a bug in 
gfortran for Windows, version: 
"GNU F95 version 4.1.0 20050702 (experimental) (i686-pc-mingw32)"

It concerns values of type real, which both print and add 
incorrectly. 

To give an example, take this little program: 

------------------------------------------------
program realtrouble
   real :: x
   integer :: i

   x=1.0
   i=5

   write(*,*) "x==",x    ! Prints 0.0 instead of 1.0 !!! 
   write(*,*) "x==",1.0  ! Prints 0.0 too !!! 
   write(*,*) "i==",i    ! Prints 5, as expected
end program realtrouble
------------------------------------------------------

Apart from incorrect results of write()ing: when summing 
several values of type real, adding 0.0 to 0.0 yielded 2.0, 
adding another 0.0 to 2.0 yielded 0.0 again! 

I've compiled and linked the program at the command-line 
under Windows XP with no particular flags, simply like this: 
    gfortran gftest.f95

Here's what a verbose execution produced: 
Driving: gfortran gftest.f95 -v -lgfortranbegin -lgfortran
Using built-in specs.
Target: i686-pc-mingw32
Configured with: ../gcc/configure --prefix=/mingw --enable-languages=c,f95
Thread model: win32
gcc version 4.1.0 20050702 (experimental)
 c:/gfortran/bin/../libexec/gcc/i686-pc-mingw32/4.1.0/f951.exe gftest.f95 -
quiet -dumpbase gftest.f9
5 -mtune=pentiumpro -auxbase gftest -version -o C:\DOKUME~1\Tillmann\LOKALE~1
\Temp/ccWqbaaa.s
GNU F95 version 4.1.0 20050702 (experimental) (i686-pc-mingw32)
        compiled by GNU C version 3.4.4 (mingw special).
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
 as -o C:\DOKUME~1\Tillmann\LOKALE~1\Temp/ccIHcaaa.o C:\DOKUME~1
\Tillmann\LOKALE~1\Temp/ccWqbaaa.s
 c:/gfortran/bin/../libexec/gcc/i686-pc-mingw32/4.1.0/collect2.exe -Bdynamic 
C:/fortran/g95/lib/crt2
.o -Lc:/gfortran/bin/../lib/gcc/i686-pc-mingw32/4.1.0 -
Lc:/gfortran/bin/../lib/gcc -LC:/fortran/g95/
lib -Lc:/gfortran/bin/../lib/gcc/i686-pc-mingw32/4.1.0/../../.. C:\DOKUME~1
\Tillmann\LOKALE~1\Temp/c
cIHcaaa.o -lgfortranbegin -lgfortran -lmingw32 -lgcc -lmoldname -lmingwex -
lmsvcrt -luser32 -lkernel
32 -ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt
--------------------------------------

I've exchanged mails with Steven Kargl, who suggested to 
produce a .original-file using flag "-fdump-tree-original". 

This generated the following: 
MAIN__ ()
{
  real4 x;
  int4 i;

  x = 1.0e+0;
  i = 5;
  _gfortran_filename = "gftest.f95";
  _gfortran_line = 8;
  _gfortran_ioparm.unit = 6;
  _gfortran_ioparm.list_format = 1;
  _gfortran_st_write ();
  _gfortran_transfer_character ("x==", 3);
  _gfortran_transfer_real (&x, 4);
  _gfortran_st_write_done ();
  _gfortran_filename = "gftest.f95";
  _gfortran_line = 9;
  _gfortran_ioparm.unit = 6;
  _gfortran_ioparm.list_format = 1;
  _gfortran_st_write ();
  _gfortran_transfer_character ("x==", 3);
  {
    real4 C.473 = 1.0e+0;

    _gfortran_transfer_real (&C.473, 4);
  }
  _gfortran_st_write_done ();
  _gfortran_filename = "gftest.f95";
  _gfortran_line = 10;
  _gfortran_ioparm.unit = 6;
  _gfortran_ioparm.list_format = 1;
  _gfortran_st_write ();
  _gfortran_transfer_character ("i==", 3);
  _gfortran_transfer_integer (&i, 4);
  _gfortran_st_write_done ();
}
------------------------------------ 

Steve's preliminary conclusion is (quote):
"(...).original shows that the gfortran frontend is
doing the right thing.  This is a gfortran library problem
or an interface with OS library problem." 

Kind regards 
   Tillmann Wegst

-- 
           Summary: real-values print and add incorrectly (version 4.1.0
                    20050702, i686-pc-mingw32)
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: post at tillmann-wegst dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-29 18:54 -------
I cannot reproduce this with 20050729 on i686-pc-linux-gnu.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|fortran                     |libfortran
 GCC target triplet|                            |i686-pc-mingw32


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[post at tillmann-wegst dot de]

------- Additional Comments From post at tillmann-wegst dot de  2005-07-29 19:01 -------
(In reply to comment #1)
> I cannot reproduce this with 20050729 on i686-pc-linux-gnu.

Yes, Steve Kargl has told me the same. The bug appears to be particular with 
the MinGW-version. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[jvdelisle at gcc dot gnu dot org]

------- Additional Comments From jvdelisle at gcc dot gnu dot org  2005-07-30 06:31 -------
I have confirmed this bug on cygwin.  We can't get current builds on cygwin,
perhaps patch to pr21275 is needed?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[fxcoudert at gcc dot gnu dot org]

------- Additional Comments From fxcoudert at gcc dot gnu dot org  2005-07-30 10:56 -------
Marked as confirmed due to Jerry's comment. Right now, building on mingw is an awful pain (4 PR 
preventing the build), and cygwin is only a bit better. So, I think work on that point is useless until the 
situation gets clearer.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-07-30 10:56:59
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[dannysmith at users dot sourceforge dot net]

------- Additional Comments From dannysmith at users dot sourceforge dot net  2005-07-31 00:56 -------
This may be the problem:

In mk-kinds-h.sh:

case $largest_ctype in
  float) echo "#define GFC_REAL_LARGEST_FORMAT \"\"" ;;
  double) echo "#define GFC_REAL_LARGEST_FORMAT \"l\"" ;;
  "long double") echo "#define GFC_REAL_LARGEST_FORMAT \"L\"" ;;
  *) echo "$0: Unknown type" >&2 ; exit 1 ;;
esac



Although mingw supports long double math, the native msvcrt.dll runtime printf 
family does not. The 'L' format specifier is ignored and passing long doubles 
to printf doesn't work at all--the values are interptreted as doubles.  The 
same problem occurs in libstdc++ and the unsatisfacpory hack that mingw distros 
use is to cast long doubles to doubles before sending to snprintf. 

Danny


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[fxcoudert at gcc dot gnu dot org]

------- Additional Comments From fxcoudert at gcc dot gnu dot org  2005-08-01 21:46 -------
(In reply to comment #5)
> Although mingw supports long double math, the native msvcrt.dll runtime printf 
> family does not.

OK. I plan to do the following (hopefully in the next few days): add a configure
test and a macro HAVE_PRINTF_THAT_WORKS_WITH_LONG_DOUBLE, and in case it's not
defined (such as for mingw) provide a fallback function to avoid that printf.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values print and add incorrectly (version 4.1.0 20050702, i686-pc-mingw32)

[fxcoudert at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |fxcoudert at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-07-30 10:56:59         |2005-08-02 07:40:27
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values are printed incorrectly

[fxcoudert at gcc dot gnu dot org]

------- Additional Comments From fxcoudert at gcc dot gnu dot org  2005-08-03 07:21 -------
I've got a patch that should work, but can't test it because of PR23210.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |23210
            Summary|real-values print and add   |real-values are printed
                   |incorrectly (version 4.1.0  |incorrectly
                   |20050702, i686-pc-mingw32)  |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values are printed incorrectly

[fxcoudert at gcc dot gnu dot org]

-- 
Bug 23138 depends on bug 23210, which changed state.

Bug 23210 Summary: i686-pc-mingw32/libssp: C compiler cannot create executables
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23210

           What    |Old Value                   |New Value
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138

[Bug libfortran/23138] real-values are printed incorrectly

[fxcoudert at gcc dot gnu dot org]

------- Additional Comments From fxcoudert at gcc dot gnu dot org  2005-08-05 22:01 -------
Patched tested and submitted to review
(http://gcc.gnu.org/ml/gcc-patches/2005-08/msg00338.html).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2005-
                   |                            |08/msg00338.html
           Keywords|                            |patch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23138