Asking about how to run peephole

[Dong Phuong]

I'm porting for microcontroller C166. I've defined
some peepholes in machine description file C166.md.
When I configured and made cc1 file, everything seemed
to be OK. 

But when I tried to compile some C program into
assembly code, I've realized that the peepholes I had
defined  didn't run. I've tried some options -O1, -O2 
but it still didn't run. 

I don't know if I have to define some special options
so that my peepholes can run. 

If you know why, would you please explain me.
Thank you for your help.