3.5.1 What's the Difference Between a Free and PRO Compiler?

The purchase of a compiler license allows the compiler to operate in PRO mode, with more advanced optimizations. These include level -O3 and -Os optimizations, as well as other compiler-specific optimization features.

Without a license, the compiler will operate in Free mode. In this mode, the compiler can build for all devices and use all the available memory for the selected device, but it will be limited to at most level -O2 optimizations. This makes the generated output of an unlicensed compiler less efficient than that of a licensed compiler, meaning that project code will require more memory and be slower to execute.