Re: spurious out-of-bounds warning message

[Arjen Markus <arjen.markus895@gmail.com>]

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I would say it is indeed very hard to capture all false positves.

Regards,

Arjen

Op wo 12 jul 2023 om 17:05 schreef Vivek Rao via Fortran <
fortran@gcc.gnu.org>:

> For the code
>
> program main
> implicit none
> integer, parameter :: n = 10
> real :: x(n), dx(n)
> integer :: i
> call random_number(x)
> do i=1,n
>    if (i > 1) then
>       dx(i) = x(i) - x(i-1)
>    else
>       dx(i) = 0.0
>    end if
> end do
> print*,dx
> end program main
>
> gfortran -Wextra says for GNU Fortran (GCC) 13.0.0 20221218
>
> xspur.f90:9:23:
>
>
>     7 | do i=1,n
>       |        2
>     8 |    if (i > 1) then
>     9 |       dx(i) = x(i) - x(i-1)
>       |                       1
> Warning: Array reference at (1) out of bounds (0 < 1) in loop beginning at
> (2) [-Wdo-subscript]
>
> but the code is fine because of the if guard. Ideally such spurious
> messages would be suppressed, but I don't know if this is too hard.
>
> Vivek Rao
>