• Upgrade the Glibc library to version 2.22 or higher. It supports SIMD directives in OpenMP* 4.0 or higher.
• Upgrade the GNU* gcc compiler to version 4.9 or higher. It supports vectorized math function options.
• Use the -fopenmp and -ffast-math compiler options to enable vector math functions.
• Use appropriate OpenMP SIMD directives to enable vectorization.

Note : Also use the -I/path/to/glibc/install/include and -L/path/to/glibc/install/lib compiler options if you have multiple Glibc libraries installed on the host.

Example

gfortran PROGRAM.FOR -O2 -fopenmp -ffast-math -lrt -lm -mavx2

...
!$OMP SIMD
do i=1,N
...

gfortran PROGRAM.FOR -O2 -fopenmp -ffast-math -lrt -lm -mavx2

program main
    parameter (N=100000000)
    real*8 angles(N), results(N)
    integer i
    call srand(86456)

    do i=1,N
        angles(i) = rand()
    enddo

    !$OMP SIMD
    do i=1,N
        results(i) = cos(angles(i))
    enddo

end