I keep ignoring nim for some reason. How fast is it with all the checks on? The benchmarks for it julia, and swift typically turn off safety checks, which is not how I would run them.

Since anything/0 = infinity, these kinds of things always depend upon what programs do and as a sibling comment correctly observes how much they interfere with SIMD autovectorization and sevral other things.

That said, as a rough guideline, nim c -d=release can certainly be almost the same speed as -d=danger and is often within a few (single digits) percent. E.g.:

    .../bu(main)$ nim c -d=useMalloc --panics=on --cc=clang -d=release -o=/t/rel unfold.nim
    Hint: mm: orc; opt: speed; options: -d:release
    61608 lines; 0.976s; 140.723MiB peakmem; proj: .../bu/unfold.nim; out: /t/rel [SuccessX]
    .../bu(main)$ nim c -d=useMalloc --panics=on --cc=clang -d=danger -o=/t/dan unfold.nim
    Hint: mm: orc; opt: speed; options: -d:danger
    61608 lines; 2.705s; 141.629MiB peakmem; proj: .../bu/unfold.nim; out: /t/dan [SuccessX]
    .../bu(main)$ seq 1 100000 > /t/dat
    .../bu(main)$ /t
    /t$ re=(chrt 99 taskset -c 2 env -i HOME=$HOME PATH=$PATH)
    /t$ $re tim "./dan -n50 <dat>/n" "./rel -n50 <dat>/n"
    225.5 +- 1.2 μs (AlreadySubtracted)Overhead
    4177 +- 15 μs   ./dan -n50 <dat>/n
    4302 +- 17 μs   ./rel -n50 <dat>/n
    /t$ a (4302 +- 17)/(4177 +- 15)
    1.0299 +- 0.0055
    /t$ a 299./55
    5.43636... # kurtosis=>5.4 sigmas is not so significant

Of course, as per my first sentence, the best benchmarks are your own applications run against your own data and its idiosyncratic distributions.

EDIT: btw, /t -> /tmp which is a /dev/shm bind mount while /n -> /dev/null.

In Julia, at least, bounds checks tend to be a pretty minor hit (~20%) unless the bounds check gets in the way of vectorization