Unable to suppress bound checking - gcc

Question

Firstly, I wasn't aware that bound checking was automatic when using gfortran. With the following code:
gfortran -Wno-array-bounds initial_parameters.f08 derrived_types.f08 lin_alg.f08 constitutive_models.f08 input_subs.f08 Subprograms.f08 mainprog.f08
I still receive the compile time warnings:
Warning: Array reference at (1) is out of bounds (3 > 2) in dimension 2
I am probably being silly here but from reading this, I thought that -Wno-array-bounds was supposed to suppress this warning? Compiling with -w successfully inhibits all warnings.
I don't know if it's relevant but the source of these warning are "Subprograms.f08" and "constitutive_models.f08" which are both modules containing subroutines and are used in the main program.
The same behaviour occurs if I attempt to compile an individual module with
gfortran -Wno-array-bounds -c constitutive_models.f08

Answer 1

I can confirm that compile warning with gfortran (4.4) with this simple code:
integer,parameter::dim=3
integer :: x(2)
if(dim.eq.1)write(*,*)x(dim)
end
Warning: Array reference at (1) is out of bounds (3 > 2) in dimension 2
this could arguably be considered a bug since one would expect the compiler to optimize out the whole if statement. Note ifort compiles this just fine.
a very simple workaround fixes this example:
integer,parameter::dim=3
integer :: x(2),dimx=dim
if(dim.eq.1)write(*,*)x(dimx)
end
of course since its just a warning, and you know its not a problem, you can choose to ignore it too !
note the use of the parameter in the logical, in case the compiler feels like optimizing it later.

Answer 2

So what I may suggest is to use overloaded subroutines in order to process the data - then you would have generic behavior without the need to pass the dimension argument explicitly to the function(thus getting rid of the warning). And then I would recommend you to follow Holmz's advice regarding using all warnings during testing stage and then completely turning them off during production build (-w). For now I wasn't able to find an efficient way of suppressing this warning (apart from -w) - it seems that the check for array bounds is on by default and is not overridden -fno-bounds-check or -Wno-array-bounds. But overloaded functions can be a better solution to your problem, the implementation should look like this in this case:
module functions
implicit none
interface test_dim
module procedure test_func1d, test_func2d, test_func3d
end interface ! test_dim
contains
subroutine test_func1d(input1d)
real, intent(in) :: input1d(:)
print*, "DOING 1 DIM"
print*, "SHAPE OF ARRAY:", shape(input1d)
end subroutine test_func1d
subroutine test_func2d(input2d)
real, intent(in) :: input2d(:,:)
print*, "DOING 2 DIM"
print*, "SHAPE OF ARRAY:", shape(input2d)
end subroutine test_func2d
subroutine test_func3d(input3d)
real, intent(in) :: input3d(:,:,:)
print*, "DOING 3 DIM"
print*, "SHAPE OF ARRAY:", shape(input3d)
end subroutine test_func3d
end module functions
program test_prog
use functions
implicit none
real :: case1(10), case2(20,10), case3(30, 40, 20)
call test_dim(case1)
call test_dim(case2)
call test_dim(case3)
end program test_prog
And the output produced by this function looks like this:
DOING 1 DIM
SHAPE OF ARRAY: 10
DOING 2 DIM
SHAPE OF ARRAY: 20 10
DOING 3 DIM
SHAPE OF ARRAY: 30 40 20