Fortran 2018 contiguous arrays are discussed in pp.139-145 of "Modern Fortran Explained: Incorporating Fortran 2018".
In general, operating on contiguous arrays is faster than non-contiguous arrays.
However, if copy-in, copy-out is needed from non-contiguous arrays, the speed benefit is not guaranteed.
For the basic case, a non-contigous array will have a temporary array copy made for the operation.
It seems that GNU Fortran may have a bug across several Gfortran versions (including Gfortran 4.8 through 8.2) where a non-contiguous array actual argument into a contiguous subroutine dummy argument leads to SIGSEGV or SIGABRT, except for very small arrays.
This did not seem to be affected by system ulimit size or by -fmax-stack-var-size.
Other compilers such as ifort, flang, and pgf90 had no problem with the same test program.
This example uses preprocessing to handle the additional annoyance that Gfortran through at least version 8 did not support Fortran 2008 intrinsic is_contiguous().