[kristofferc]

Your code only shows that

    gen_sinwave(113.0)

calls

    gen_sinwave(1113.0, 0.0, 0.1)

(which are the default arguments). It is usually better to use @code_llvm because the LLVM IR is typically easier to read.

    julia> @code_llvm gen_sinwave(1113.0);
    
    ; Function gen_sinwave
    ; Location: REPL[2]:2
    define nonnull %jl_value_t addrspace(10)* 
    @julia_gen_sinwave_345638059(double) {
    top:
      %1 = call nonnull %jl_value_t addrspace(10)* @julia_gen_sinwave_345638060(double %0, double 0.000000e+00, double 1.000000e-01)
      ret %jl_value_t addrspace(10)* %1
    }

However, defining

    function gen_sinwave(freq, init=0.0, step=0.1)
        data = collect(init:step:freq)
        fin9_shaper.(data)
    end

and looking at

    @code_llvm gen_sinwave(1113.0, 0.0, 1.0)

we can see that there is a lot of auto-vectorization going on