Features
- Operand classes for instructions
- Hints in register allocation
- Fixed register instructions (div, mul)
  Is this part of "operand classes"?

Instructions
- ADD SUB SDIV UDIV SREM UREM MUL LSL LSR ASL ASR
- SEXT ZEXT
- CMP ...
- ALLOC STORE LOAD
- PTR
- CALL BRZ JMP RET

Types
- Integer (64 bits)
- Structure "{a,b,c}"
- Pointer to type "t"

Questions
- Should we allow constant operands?