0. Define how many physical regs are available, which are caller-saved and callee-saved
1. Implement if-else and while statements
2. Find out what use[B] and def[B] are for each block
3. Define successors and predecessors of each block and make them accessible
4. Compute liveIn[B] and liveOut[B] for each block
  
  Classic equations:

  liveIn[B] = use[B] ∪ (liveOut[B] - def[B])

  liveOut[B] = ⋃ liveIn[S] for S in succ[B]
5. Linear scan register allocation


- Instruction numbering + per-instruction liveness
- Live intervals
- Linear scan allocator with ~6 fake regs
- Spill to stack slots
- Add “CALL clobbers regs” rule


function's reserved registers:
  EAX, ECX, EDX

return registers:
  int => EAX
  float => ST0