Thee following program gives wrong results for some of the array elements in an assignment when there is an overlap between the left hand and right hand arrays. The errors sometimes move around as I modified the code (although I've changed enough things that I can't reproduce different failures. Changing the U* variables from arrays of structures to scalar structures (still with an array component) makes the errors go away.
Dick Hendrickson
! fails on Windows XP
! gcc version 4.4.0 20080603 (experimental) [trunk revision 136333] (GCC)
!Gives wrong answers for tests 1 and 3
!Gives correct answers if the dimensions of the various U arrays are removed
!
! The errors sometimes change as I moved code around to isolate a test case
! I have other similar tests with a left-right hand side overlap (and often
! negative strides) that fail in the large, but work when reduced to
! a simple subroutine.
module cg0071_mod
type seq
integer ia(10,10)
end type
contains
SUBROUTINE CGAM02(UDA,nf3,nf9,nf10,nf1,mf1)
TYPE (SEQ) :: UDA(4)
UDA( 3)%IA( 1: 9, 1: 10) =
$UDA( 3)%IA( 9: 1:-1, 10: 1:-1)+1
END SUBROUTINE
end module
program try_cg0071
use cg0071_mod
TYPE(SEQ) UDA1L(4)
TYPE(SEQ) UDA1R(4)
type(seq) utest(4)
do j1 = 1,10
do j2 = 1,10
uda1r%ia(j1,j2) = j1 + 10*(j2-1)
uda1l%ia(j1,j2) = 10000 + uda1r%ia(j1,j2)
enddo
enddo
call cg0071(uda1l,uda1r,4)
end
SUBROUTINE CG0071(UDA1L,UDA1R,nf4)
! COPYRIGHT 1999 SPACKMAN & HENDRICKSON, INC.
use cg0071_mod
TYPE(SEQ) UDA1L(4)
TYPE(SEQ) UDA1R(4)
type(seq) utest(4)
type(seq) uda(4)
UDA1L = UDA1R
utest = uda1r
uda = uda1r
CALL CGAM02(UDA1L,3,9,10,1,-1) !1st test
Utest( 3)%IA( 1: 9, 1: 10) = !2nd test
$UDA1r( 3)%IA( 9: 1:-1, 10: 1:-1)+1
UDA( 3)%IA( 1: 9, 1: 10) = !3rd test
$UDA( 3)%IA( 9: 1:-1, 10: 1:-1)+1
print *,' expected actual'
print *, 'first test same dummy arg on left and right'
DO J1 = 1,9
DO J2 = 1,10
if (UDA1R(3)%IA(10-J1,11-j2)+1
$/= UDA1L(3)%IA(J1,J2))
$ print *, j1, j2, uda1r(3)% ia(10-J1,11-j2)+1 ,
$UDA1L(3)%IA(J1,J2)
ENDDO; ENDDO
print *, 'second test different arrays on left and right'
DO J1 = 1,9
DO J2 = 1,10
if (UDA1R(3)%IA(10-J1,11-j2)+1
$/= Utest(3)%IA(J1,J2))
$ print *, j1, j2, uda1r(3)% ia(10-J1,11-j2)+1 ,
$Utest(3)%IA(J1,J2)
ENDDO; ENDDO
print *, 'third test, same local array on left and right'
DO J1 = 1,9
DO J2 = 1,10
if (UDA1R(3)%IA(10-J1,11-j2)+1
$/= Uda(3)%IA(J1,J2))
$ print *, j1, j2, uda1r(3)% ia(10-J1,11-j2)+1 ,
$Uda(3)%IA(J1,J2)
ENDDO; ENDDO
END SUBROUTINE
C:\gfortran>gfortran cg0071.f
C:\documents and settings\s and h\my documents\g_experiments\gfortran>a
expected actual
first test same dummy arg on left and right
1 6 50 53
1 7 40 63
1 8 30 73
1 9 20 83
1 10 10 93
2 6 49 54
2 7 39 64
2 8 29 74
2 9 19 84
2 10 9 94
3 6 48 55
3 7 38 65
3 8 28 75
3 9 18 85
3 10 8 95
4 6 47 56
4 7 37 66
4 8 27 76
4 9 17 86
4 10 7 96
5 6 46 57
5 7 36 67
5 8 26 77
5 9 16 87
5 10 6 97
6 6 45 58
6 7 35 68
6 8 25 78
6 9 15 88
6 10 5 98
7 6 44 59
7 7 34 69
7 8 24 79
7 9 14 89
7 10 4 99
8 6 43 60
8 7 33 70
8 8 23 80
8 9 13 90
8 10 3 100
9 6 42 61
9 7 32 71
9 8 22 81
9 9 12 91
9 10 2 101
second test different arrays on left and right
third test, same local array on left and right
1 6 50 53
1 7 40 63
1 8 30 73
1 9 20 83
1 10 10 93
2 6 49 54
2 7 39 64
2 8 29 74
2 9 19 84
2 10 9 94
3 6 48 55
3 7 38 65
3 8 28 75
3 9 18 85
3 10 8 95
4 6 47 56
4 7 37 66
4 8 27 76
4 9 17 86
4 10 7 96
5 6 46 57
5 7 36 67
5 8 26 77
5 9 16 87
5 10 6 97
6 6 45 58
6 7 35 68
6 8 25 78
6 9 15 88
6 10 5 98
7 6 44 59
7 7 34 69
7 8 24 79
7 9 14 89
7 10 4 99
8 6 43 60
8 7 33 70
8 8 23 80
8 9 13 90
8 10 3 100
9 6 42 61
9 7 32 71
9 8 22 81
9 9 12 91
9 10 2 101
--
Summary: wrong result for left-right hand side array overlap and
(possibly) negative strides
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dick dot hendrickson at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37723
