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.
A non-contiguous array actual argument into a contiguous subroutine dummy argument is incorrect syntax.
GCC < 9 may fail with SIGSEGV or SIGABRT in this case, dependent on array size.
Other compiler correct this incorrect syntax by temporary array opy-in, copy-out which is slower.
.\build\contiguous\contig.exe
At line 56 of file ../contiguous/contiguous.f90
Fortran runtime warning: An array temporary was created
F contig: 0.001 sec.
T contig: 0.005 sec.