DISCLAIMER: These notes are from the defunct k8 project which precedes SquirrelJME. The notes for SquirrelJME start on 2016/02/26! The k8 project was effectively a Java SE 8 operating system and as such all of the notes are in the context of that scope. That project is no longer my goal as SquirrelJME is the spiritual successor to it.
For SSAProgram settings I have EXTERN_INT_PROMOTE and EXTERN_FLOAT_PROMOTE which take would auto promote lower integer values to higher types. However that can just be done automatically (say if a byte is copied into an integer register). As I thought of before, integers, floating point, and references could be in their groups. On another note, I can merge SSAVariable and SSARegister together as a subclass of some other class. I also need a stronger type system which can use unsigned values and such of arbitrary size.
Not too sure how I would want to handle program arguments. I suppose there would just be an implicit set of variables which exist.