josopait,
Is this the IL generated by brook+? Or are you looking at the ISA generated by the cal compiler? The IL generated by brook+ uses a virtual instruction set and has an unlimited register set, so there is no worries in that aspect. If you want more control over the code generation, you need to move down to programming at the CAL/IL level. That way you can see exactly what IL instructions are mapping to what ISA instructions. At the brook+ level, it is a lot harder to see what that mapping is.