- refactor, avoid gigapolymorphism with freg2 and use aliases instead (works
same on x86/arm) (at least by the assembly stage)
- make sure f2 constants are lifted out of loops..
- [½] properly preserve volatile parts of registers across calls...
- make calls more efficient (all at once + give offsets)
- successive difference simd
- frange SIMD
- [½] constant lift-out-of-loop (SIMD)