https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85737
Bug ID: 85737
Summary: gfortran 8.1.0 false positive with -Wdo-subscript
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: spapanik21 at gmail dot com
Target Milestone: ---
After the update to gcc-fortran 8.1.0 the following program:
program false_positive
integer, dimension(5, 5) :: matrix = reshape( &
(/ &
32, 63, 93, 53, 69, &
32, 40, 62, 76, 36, &
85, 74, 14, 36, 16, &
16, 23, 57, 15, 54, &
11, 89, 19, 67, 48 &
/), &
shape(matrix), &
order=(/ 2, 1 /) &
)
integer :: i, j, m, n
m = size(matrix, 1)
n = size(matrix, 2)
do i = 1, m
do j = 1, n
if (j > 4) then
print *, matrix(i, j - 3)
end if
end do
end do
end program false_positive
produces the following warning:
stephanos@darwin $ gfortran -Wdo-subscript -c fp.f90
fp.f90:20:35:
fp.f90:18:19:
do j = 1, n
2
fp.f90:20:35:
print *, matrix(i, j - 3)
1
Warning: Array reference at (1) out of bounds (-2 < 1) in loop beginning at (2)
[-Wdo-subscript]
The warning was not present in gcc-fortran 7.3.1
