https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60670
--- Comment #13 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> --- Showing how the module files are not found when a non default multilib is chosen: $ gfortran a.f90 -fopenmp $ gfortran a.f90 -fopenmp -m32 a.f90:1:6: use omp_lib 1 Fatal Error: Can't open module file ‘omp_lib.mod’ for reading at (1): No such file or directory compilation terminated. $ cat a.f90 use omp_lib end