sincos.jl

function sincos(x)
    psin = Cdouble[0]; pcos = Cdouble[0]
    ccall(:sincos, Void, (Cdouble, Ptr{Cdouble}, Ptr{Cdouble}), x, psin, pcos)
    psin[1], pcos[1]
end

function foo(X)
    ta = 0.0
    tb = 0.0
    for x in X
        a = sin(x)
        b = cos(x)
        ta += a
        tb += b
    end
    ta, tb
end

function bar(X)
    ta = 0.0
    tb = 0.0
    for x in X
        a, b = sincos(x)
        ta += a
        tb += b
    end
    ta, tb
end

N = 1_000_000
X = rand(N)
@time foo(X)
@time bar(X)