dg6@fusiont6-1:~/code/genray$ gfortran --version
GNU Fortran (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
make -f makefile_gfortran64
internal compiler error: in split_loop, at tree-ssa-loop-split.c:566
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions.
makefile_gfortran64:89: recipe for target 'mullerfun2.o' failed
make: *** [mullerfun2.o] Error 1