Depending on the complexity of your source and the options you have chosen, the compiler will shut off optimizations when certain parameters are exceeded. When you have additional subroutines in the file, optimizations remain shut down. The option -override_limits should maintain the options you have set, at the possible expense of time and disk space.

There are a variety of possible resources which could trigger such a warning. It may be related to compiling vary large subroutines at high optimization levels. In such cases, you might consider splitting the large routine into smaller components.

I encourage you to submit an issue to Intel Premier Support at https://premier.intel.com , quoting your full command line (you can say that I advised this). You should get additional detail and advice.

Martyn