[Bug fortran/38285] New: Wrong I/O output: Interaction between F and P for output

[Bug fortran/38285] New: Wrong I/O output: Interaction between F and P for output

[burnus at gcc dot gnu dot org]

Found on the J3 mailing list. gfortran is the compiler which prints "0.0"as
second number (4.1 to 4.4); ifort, g95, NAG f95, openf95 and sunf95 print the
3742 twice.

Van Snyder writes:
--------------------------------------------------------
The list items in subclause 10.8.5 "P editing" of 08-007r2 that begin
"On output,..." are silent concerning the effect of P editing on F
editing for output.  The specification of the effect of P on F during
output is hiding in the first list item, which begins "On input,...."

With the little program

        program F_and_P

          print 1, 3742.0, 0.3742
        1 format ( f14.0, 4pf14.0 )

        end program F_and_P

five of my six compilers produce a program that (correctly) prints
         3742.         3742.
while one (incorrectly) prints
         3742.         0000.

This treatment of F and P interaction goes back to F66 (7.2.3.5.1,
7.2.3.6.2), F77 (13.5.7.1, 13.5.9.2.1), and f90/95 (10.6.5, 10.5.1.2.1).

The effect of P on F output would be more clearly explained in a
separate list item, say between the second and third items.  I don't
think it's possible to rearrange the first list item both to be correct
and not to hide either the input or output effect.


-- 
           Summary: Wrong I/O output: Interaction between F and P for output
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2008-11-27 09:37 -------
This is a regression with regards to g77.

The email itself (for completeness):
http://j3-fortran.org/pipermail/j3/2008-November/002084.html

The problem only occurs for a d (Fw.d) of "0", for, e.g., "4PF14.1" gfortran
and the other compilers print: "3742.0".

Thus, I think the problem is the special case for abs(internal number) < 0
together with Fw.d with d == 0.


>From the F2003 standard: "10.7.5 P editing"
"The kP edit descriptor temporarily changes (9.4.1) the scale factor for the
connection to k. The scale factor affects the editing of F, E, EN, ES, D, and G
edit descriptors for numeric quantities."
[...]
"(1) On [...] F output editing, the scale factor effect is that the externally
represented number equals the internally represented number multiplied by
10^k."


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |4.1.3 4.2.1 4.3.2 4.4.0
      Known to work|                            |3.4.6


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[jvdelisle at gcc dot gnu dot org]

------- Comment #2 from jvdelisle at gcc dot gnu dot org  2008-11-27 14:21 -------
I will see what I can do.


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jvdelisle at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-11-27 14:21:54
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[jvdelisle at gcc dot gnu dot org]

------- Comment #3 from jvdelisle at gcc dot gnu dot org  2008-11-28 19:58 -------
*** Bug 38305 has been marked as a duplicate of this bug. ***


-- 

jvdelisle at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fkrogh#gcc at mathalacarte
                   |                            |dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[jvdelisle at gcc dot gnu dot org]

------- Comment #4 from jvdelisle at gcc dot gnu dot org  2008-12-05 04:09 -------
Subject: Bug 38285

Author: jvdelisle
Date: Fri Dec  5 04:07:45 2008
New Revision: 142455

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142455
Log:
2008-12-04  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR fortran/38285
        * write_float.def (WRITE_FLOAT): Zero the float value for special case
        only if scale_factor = 0.

Modified:
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/io/write_float.def


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[jvdelisle at gcc dot gnu dot org]

------- Comment #5 from jvdelisle at gcc dot gnu dot org  2008-12-05 04:12 -------
Subject: Bug 38285

Author: jvdelisle
Date: Fri Dec  5 04:11:28 2008
New Revision: 142456

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142456
Log:
2008-12-04  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR libfortran/38285
        gfortran.dg/fmt_f_an_p.f: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/fmt_f_an_p.f
Modified:
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285

[Bug fortran/38285] Wrong I/O output: Interaction between F and P for output

[jvdelisle at gcc dot gnu dot org]

------- Comment #6 from jvdelisle at gcc dot gnu dot org  2008-12-05 05:03 -------
Fixed on trunk.


-- 

jvdelisle at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38285