Thank you for your reply, Stefan_Salewski. And I'm sorry that my reply was too late.
I tried using `--gc:regions`. However, probably due to that gc works fine, the speed of the execution of my program became very slow. So after all I rewrote the program so that it works without gc (for example, making initializing of the structure only once and reusing it, avoiding using string, and so on). And it worked fine. Thank you again.
