[masklinn]

> Optimizing that code is not so easy, especially if that involves inlining C code (I wouldn't try, if possible)

Inlining through C code probably isn't really an option[0], but the optimisation itself shouldn't be that much of an issue, the rust version and the equivalent imperative loop compile to the exact same code: https://godbolt.org/g/OJHIwc[1]

[0] unless you interpret — and can JIT — the C code with the same underlying machinery as Truffle does

[1] used iter_arith for sum(), but you can replace sum() by an explicit fold for no difference: https://godbolt.org/g/R1BgQQ

[gsnedders]

> [0] unless you interpret — and can JIT — the C code with the same underlying machinery as Truffle does

Pyston can easily JIT the C code because it uses LLVM for it's main JIT tier.