Possible inefficiency in randn!

General Usage Performance
5

I was confused in the previous post, sorry. That has nothing to do with simd:

using Random
broadcast_randn(x) = (x .= randn.())
inplace_randn(x) = randn!(x)

function myrandn!(x)
    @inbounds @simd for i in eachindex(x)
        x[i] = randn()
    end
    x
end

function myrandn_nosimd!(x)
    @inbounds for i in eachindex(x)
        x[i] = randn()
    end
    x
end


x = zeros(10_000)
@btime broadcast_randn($x);
@btime inplace_randn($x);
@btime myrandn!($x);
@btime myrandn_nosimd!($x);

is only slow in inplace_randn. The real difference in the two cases is that randn isn’t inlined in randn!. This is despite randn being marked as @inline, so it looks like the inlining heuristics are being too conservative here.