Apparently, the Fortran standard does not enforce the short-circuit evaluation. Although gfortran performs it at the optimization levels -O1 and higher, the runtime out-of-bounds check, generated with the -fbounds-check compiler flag, works as if there were no short-circuiting. Therefore, IF (k == 1 .OR. ... OutputArray(k - 1) ... results in Fortran runtime error: Index '0' of dimension 1 of array 'outputarray' below lower bound of 1 when k == 1.
This MR makes the code (in a rather awkward way) independent of the short-circuit optimizations to avoid possible out-of-bounds memory access. Additionally, CI jobs that test with gfortran now build with the -fbounds-check Fortran compiler flag.
