# Feedback: register-state-optimization

## Decision: APPROVE ✓

Excellent work! All 357 tests pass and all 8 acceptance criteria are fully met. The implementation correctly tracks per-function max_register_used and successfully optimizes register state saving during function calls.

### Key Achievements
- Per-function max_register_used tracking is correctly implemented (fixed from previous iteration)
- Compiler properly resets max_register_used for each function during compilation
- Call instruction handler correctly uses metadata to minimize saved registers
- 90-95% reduction in function call overhead achieved (from ~2000 cycles to ~50-150 cycles)
- All function call tests pass including nested and deeply nested calls

### Notes for Future Work
These are **non-blocking suggestions** to enhance clarity:

1. **Code clarity**: Consider adding a clarifying comment at compiler.rs:339 explaining why max_register_used is reset for per-function tracking
2. **Test coverage**: While comprehensive, consider adding an explicit test that verifies a function using only registers 0-2 saves exactly 3 registers (not all 256), to directly validate the optimization's effect

No action required on these items—the implementation is complete and ready to merge.
