[Bug fortran/38135] New: FORALL gives wrong result

[Bug fortran/38135] New: FORALL gives wrong result

[burnus at gcc dot gnu dot org]

I expect that the following program prints:

    1    2    2
    2    1    2
    2    2    1
    1    0    0    0

which works with g95 and ifort, but with gfortran one gets:
    1    1*****
   72    1    1
*****   72    1
    1    0    0    0

The program is a minutely modified version of the program posted to c.l.f by
James Van Buskirk at
http://groups.google.com/group/comp.lang.fortran/browse_thread/thread/e7ec475ff7935804

integer, parameter :: N = 3
integer A(N,N)
A(1:N,1:N)=reshape([integer::],[N,N],reshape([1],[N+1],[2]))
write(*,'(3i5)') A
write(*,'(4i5)') reshape([1],[N+1],[0])
end


-- 
           Summary: FORALL gives wrong result
           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=38135

[Bug fortran/38135] FORALL gives wrong result

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2008-11-15 16:10 -------
Using
  A(1:N,1:N)=reshape(A(1:0,1),(/N,N/),reshape((/1/),(/N+1/),(/2/)))
the program is a Fortran 95 program, which also works with NAG f95 and openf95.
-> Blocking 32834


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |32834
              nThis|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] FORALL gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #2 from tkoenig at gcc dot gnu dot org  2008-11-15 17:19 -------
$ cat foo.f90
integer, parameter :: N = 3
integer A(N,N)
A(1:N,1:N)=reshape(A(1:0,1),(/N,N/),reshape((/1/),(/N+1/),(/2/)))
write(*,'(3i5)') A
write(*,'(4i5)') reshape([1],[N+1],[0])
end
$ gfortran -fbounds-check foo.f90
$ ./a.out
Fortran runtime error: Incorrect size in SOURCE argument to RESHAPE intrinsic:
is 0, should be 9

A false positive for bounds checking as well, it appears.


-- 

tkoenig at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #3 from tkoenig at gcc dot gnu dot org  2008-11-16 09:04 -------
Simplified test case (without the second reshape):

The problem appears to be the empty SOURCE with the presence of PAD.

$ cat bar.f90
program main
  integer, parameter :: N = 3
  integer :: A(N,N)
  integer :: b(n+1)

  b = (/ 1, 2, 2, 2 /)

  A(1:N,1:N)=reshape(A(1:0,1),(/N,N/),b)
  write(*,'(3i5)') A

end program main
$ gfortran bar.f90
$ ./a.out
    1*****    1
*****    1*****
    1*****    1


-- 

tkoenig at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-11-16 09:04:10
               date|                            |
            Summary|FORALL gives wrong result   |RESHAPE gives wrong result


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

------- Comment #4 from mikael at gcc dot gnu dot org  2008-11-16 11:38 -------
(In reply to comment #3)
> The problem appears to be the empty SOURCE with the presence of PAD.
I agree.

There are two bugs actually:
(1) the front-end doesn't expand the reshape. 
    (at least in this case: reshape([integer::],[N,N],[1,2,2,2]) )
(2) reshape gives wrong results. 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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------- Comment #5 from mikael at gcc dot gnu dot org  2008-11-16 13:45 -------
Index: simplify.c
===================================================================
--- simplify.c  (révision 141833)
+++ simplify.c  (copie de travail)
@@ -3410,9 +3410,6 @@ is_constant_array_expr (gfc_expr *e)
   if (e->expr_type != EXPR_ARRAY || !gfc_is_constant_expr (e))
     return false;

-  if (e->value.constructor == NULL)
-    return false;
-  
   for (c = e->value.constructor; c; c = c->next)
     if (c->expr->expr_type != EXPR_CONSTANT)
       return false;

This solves (1) (the original testcase), but not (2).
I will regtest it. 

for (2), I'm puzzled. :(


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #6 from tkoenig at gcc dot gnu dot org  2008-11-16 13:58 -------
(In reply to comment #5)

> 
> for (2), I'm puzzled. :(

I'm onto it; the problems are in reshape.m4 / reshape_generic.c .


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

------- Comment #7 from mikael at gcc dot gnu dot org  2008-11-16 15:22 -------
(In reply to comment #6)
> I'm onto it; the problems are in reshape.m4 / reshape_generic.c .
> 
Ok, leaving it to you. 

According to my tests, sstride0 has suspicious values. 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #8 from tkoenig at gcc dot gnu dot org  2008-11-16 16:03 -------
Created an attachment (id=16700)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16700&action=view)
Patch for the library part

Well, here's a patch for the library part.  Apparently, nobody ever paid much
attention to the "pad" argument before (a few things were just plain wrong
there).

Mikael, you were right about sstride0, but that wasn't the only problem :-)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

------- Comment #9 from mikael at gcc dot gnu dot org  2008-11-16 18:46 -------
(In reply to comment #8)
Are you sure this is needed ?

   if (sempty)
     {
-      /* Switch immediately to the pad array.  */
+      /* Pretend we are using the pad array the first time around, too.  */
       src = pptr;
-      sptr = NULL;
+      sptr = pptr;
       sdim = pdim;
       for (dim = 0; dim < pdim; dim++)

sptr is only used later to switch from source to pad, which is not needed here
as we start with pad directly. No?


> Mikael, you were right about sstride0, but that wasn't the only problem :-)
While we are at it, we could calculate sstride0 outside the loop, that would be
5ns faster ;-). 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

------- Comment #10 from mikael at gcc dot gnu dot org  2008-11-16 19:44 -------
(In reply to comment #9)
Those are only details, it works nicely :-).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #11 from tkoenig at gcc dot gnu dot org  2008-11-16 20:38 -------
Regression-test and full patch, including test cases, tomorrow.

RL keeps interfering :-)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[pault at gcc dot gnu dot org]

------- Comment #12 from pault at gcc dot gnu dot org  2008-11-16 22:25 -------
Thomas,

Since you are there, bar the shouting, I thought that I would assign you:-)

Cheers and thanks

Paul


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |tkoenig at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #13 from tkoenig at gcc dot gnu dot org  2008-11-18 22:44 -------
Subject: Bug 38135

Author: tkoenig
Date: Tue Nov 18 22:43:05 2008
New Revision: 141982

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=141982
Log:
2008-11-18  Thomas Koenig  <tkoenig@gcc.gnu.org>

        PR libfortran/38135
        * m4/reshape.m4:  Correct bounds checking when PAD is present.
        Treat PAD as if it were SOURCE when SOURCE is empty.
        * intrinsics/reshape_generic.c:  Likewise.
        * generated/reshape_c10.c Regenerated.
        * generated/reshape_c16.c Regenerated.
        * generated/reshape_c4.c Regenerated.
        * generated/reshape_c8.c Regenerated.
        * generated/reshape_i16.c Regenerated.
        * generated/reshape_i4.c Regenerated.
        * generated/reshape_i8.c Regenerated.
        * generated/reshape_r10.c Regenerated.
        * generated/reshape_r16.c Regenerated.
        * generated/reshape_r4.c Regenerated.
        * generated/reshape_r8.c Regenerated.

2008-11-18  Thomas Koenig  <tkoenig@gcc.gnu.org>

        PR libfortran/38135
        * gfortran.dg/reshape_pad_1.f90:  New test case.


Added:
    trunk/gcc/testsuite/gfortran.dg/reshape_pad_1.f90
Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/generated/reshape_c10.c
    trunk/libgfortran/generated/reshape_c16.c
    trunk/libgfortran/generated/reshape_c4.c
    trunk/libgfortran/generated/reshape_c8.c
    trunk/libgfortran/generated/reshape_i16.c
    trunk/libgfortran/generated/reshape_i4.c
    trunk/libgfortran/generated/reshape_i8.c
    trunk/libgfortran/generated/reshape_r10.c
    trunk/libgfortran/generated/reshape_r16.c
    trunk/libgfortran/generated/reshape_r4.c
    trunk/libgfortran/generated/reshape_r8.c
    trunk/libgfortran/intrinsics/reshape_generic.c
    trunk/libgfortran/m4/reshape.m4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #14 from tkoenig at gcc dot gnu dot org  2008-11-19 19:33 -------
The problem is fixed on trunk,  I think we can close this
after backporting.

Mikael, if you think the problem you mentioned in comment #4 warrants
its own PR, maybe you could open it.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[mikael at gcc dot gnu dot org]

------- Comment #15 from mikael at gcc dot gnu dot org  2008-11-19 20:56 -------
(In reply to comment #14)
> Mikael, if you think the problem you mentioned in comment #4 warrants
> its own PR, maybe you could open it.
> 
PR 38184 opened for that.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #17 from tkoenig at gcc dot gnu dot org  2008-11-23 15:10 -------
Fixed on 4.3.

Closing.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #16 from tkoenig at gcc dot gnu dot org  2008-11-23 15:10 -------
Subject: Bug 38135

Author: tkoenig
Date: Sun Nov 23 15:08:32 2008
New Revision: 142134

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142134
Log:
2008-11-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

        PR libfortran/38135
        Backport from trunk.
        * m4/reshape.m4:  Tread PAD as if it were SOURCE when SOURCE
        is empty.
        * intrinsics/reshape_generic.c:  Likewise.
        * generated/reshape_c10.c Regenerated.
        * generated/reshape_c16.c Regenerated.
        * generated/reshape_c4.c Regenerated.
        * generated/reshape_c8.c Regenerated.
        * generated/reshape_i16.c Regenerated.
        * generated/reshape_i4.c Regenerated.
        * generated/reshape_i8.c Regenerated.
        * generated/reshape_r10.c Regenerated.
        * generated/reshape_r16.c Regenerated.
        * generated/reshape_r4.c Regenerated.
        * generated/reshape_r8.c Regenerated.

2008-11-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

        PR libfortran/38135
        Backport from trunk.
        * gfortran.dg/reshape_pad_1.f90:  New test case.



Added:
    branches/gcc-4_3-branch/gcc/testsuite/gfortran.dg/reshape_pad_1.f90
Modified:
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_3-branch/libgfortran/ChangeLog
    branches/gcc-4_3-branch/libgfortran/generated/reshape_c10.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_c16.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_c4.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_c8.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_i16.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_i4.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_i8.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_r10.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_r16.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_r4.c
    branches/gcc-4_3-branch/libgfortran/generated/reshape_r8.c
    branches/gcc-4_3-branch/libgfortran/intrinsics/reshape_generic.c
    branches/gcc-4_3-branch/libgfortran/m4/reshape.m4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135

[Bug fortran/38135] RESHAPE gives wrong result

[tkoenig at gcc dot gnu dot org]

------- Comment #18 from tkoenig at gcc dot gnu dot org  2008-11-23 15:17 -------
... and now really closing.


-- 

tkoenig at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38135