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Truffle + Graal looks awesome. I looked at some old ZipPy slides (JIT compiler for Python) here: http://socalpls.github.io/archive/2013nov/slides/zippy.pdf

They have an example where this code is compiled:

    def sumitup(n):
        total = 0
        for i in range(n):
            total = total + i
        return total

It was optimized quite well, but still had loops. I know this is a lot to ask, but I would have expected it to be possible to specialize it to a loopless variant:

    def sumitup(n):
        if n < 0:
            return 0
        else:
            return n*(n-1) // 2

Clang 4+ actually finds this optimization, but gcc and icc doesn't seem to: https://godbolt.org/g/v4zhrm

That is, the assembly generated by clang seems to be equivalent to

    if n <= 0:
        return 0
    else:
        return ((n-1)*(n-2) >> 1) + (n-1)

which might even run faster on the CPU, due to the speficic code emitted.