Excluding parts of the instruction set during compilation

[Fabian Oboril]

Hello everybody,

I am currently working on a project for which I need to compile C-code 
using only a small subset of the available instruction set. So for 
example, instead of using add, addi, addiu and addu, I would like that 
the compiler is using just one of them. Is there a way, that this can be 
handled with gcc, for example by giving a list of not-to-use 
instructions at compile time?

Can anyone help?