This is the system
uname -a
Linux argux9.fuqua.duke.edu 2.6.18-194.3.1.el5 #1 SMP Thu May 13
13:08:30 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux
This is the compiler
gfortran44 --version
GNU Fortran (GCC) 4.4.0 20090514 (Red Hat 4.4.0-6)
Copyright (C) 2009 Free Software Foundation, Inc.
This is the problem
The bug is that the mask is supposed to be applied before the statements
within the where clause are evaluated. As can be seen from the output
the statements within the mask are evaluated before the mask is applied.
This is the relevant code
do k = 1, rows + 1
if ( (k .gt. rows) .or. (k .gt. cols) ) then
mask = .false.
else
mask = .true.
end if
where (mask)
A = b(k)
end where
end do
These are the compiler flags
-save-temps -fbounds-check
This is stderr
At line 39 of file wherebug.F90
Fortran runtime error: Array reference out of bounds for array 'b',
upper bound of dimension 1 exceeded (6 > 5)
This is the -save-temps file
a...@argux9$ cat wherebug.f90
# 1 "wherebug.F90"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "wherebug.F90"
program wherebug
implicit none
integer, parameter :: &
stdin = 5, & ! reserved unit for standard input
stdout = 6, & ! reserved unit for standard output
stderr = 0 ! reserved unit for standard error
integer, parameter :: &
i1 = selected_int_kind(2), &
i2 = selected_int_kind(4), &
i4 = selected_int_kind(9), &
i8 = selected_int_kind(18), &
r4 = kind(1.0), &
r8 = selected_real_kind(2*precision(1.0_r4)), &
r16 = selected_real_kind(2*precision(1.0_r8))
integer, parameter :: rows = 5, cols = 5
integer :: i, j, k
real(r8), dimension(rows,cols) :: A
real(r8), dimension(rows) :: b
logical, dimension(rows,cols) :: mask
A = 1.0_r8
b = 1.0_r8
mask = .true.
do k = 1, rows + 1
if ( (k .gt. rows) .or. (k .gt. cols) ) then
mask = .false.
else
mask = .true.
end if
where (mask)
A = b(k)
end where
end do
end program wherebug
--
Summary: where mask not applied before where clause evaluated
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: aronaldg at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425
