Nested modules, via nested USE statements, can sometimes degrade compile-time performance. The complexity of the nested modules can determine when the compile-time performance degradation is observed. While Intel continues to make improvements in this area, some users are still reporting slow compilation of very complex nested module use patterns.
As a work-around reduce the depth of nested modules. Here are some suggestions to accomplish this task:
Intel® Fortran Compiler for Linux* - Deeply-nested modules can cause slow compilation
For more complete information about compiler optimizations, see our Optimization Notice.