@septc has already reported above that when he uses gfortran with -check all in the solution.f90 he is still getting a temporary array warnings, so even in that case the gfortran will still copy the data no matter what constructs of the language we use.
In this perspective the Intel Fortran compiler is apparently able to fully optimize the code and not make any copies whatsoever.
Perhaps this is a desirable improvement in the gfortran compiler?