How to handle user defined functions?

I get the following error
```julia
ERROR: MethodError: no method matching calc_A(::VectorizationBase.SVec{16,Int16})
```
where `calc_A` is a user defined function. Do I need to implement `calc_A(::VectorizationBase.SVec{16,Int16})` myself? Why isn't there an error for the other user defined functions? My first guess was because they are inlined, but `calc_A` should be inlined, too.

Here is the code for that:
```julia
@inline function calc_A(x::Int16)
p = 15; r = 1; A = Int16(23170); C = Int16(-425)
n = 7
a = 7
x² = (x * x) >> n
rounding = one(x) << (p - a - 1)
(A + rounding + (x² * C) >> r) >> (p - a)
end
@inline function calc_B(x::Int16)
p = 14; r = 3; B = Int16(-17790); D = Int16(351)
n = 7
a = 7
x² = (x * x) >> n
rounding = one(x) << (p - a - 1)
(rounding + x * (B + (x² * D) >> r) >> n) >> (p - a)
end
@inline function get_first_bit_sign(x)
n = 7
mysign(x << (sizeof(x) * 8 - n - 1))
end
@inline function get_second_bit_sign(x)
n = 7
mysign(x << (sizeof(x) * 8 - n - 2))
end
@inline function get_quarter_angle(x)
n = 7
x & (one(x) << n - one(x)) - one(x) << (n - 1)
end
@inline mysign(x) = 2 * signbit(x) - 1

function gen_sincos!(sins, coss, phases)
@avx for i = 1:2500
first_bit_sign = get_first_bit_sign(phases[i])
second_bit_sign = get_second_bit_sign(phases[i])
quarter_angle = get_quarter_angle(phases[i])
A = calc_A(quarter_angle)
B = calc_B(quarter_angle)

coss[i] = second_bit_sign * (first_bit_sign * A + B)
sins[i] = second_bit_sign * (A - first_bit_sign * B)
end
end
sins = Vector{Int16}(undef, 2500)
coss = Vector{Int16}(undef, 2500)
phases = Vector{Int16}(undef, 2500)
gen_sincos!(sins, coss, phases)
```
**EDIT:** Alright I found the solution myself: If I write `function calc_A(x)` instead of `function calc_A(x::Int16)`, it will work. So should I omit the declaration of `x`? What if I have a different function for `x::Int32`?

Start with gen_sincos! and the @avx loop, then compare how calc_A is defined with the other user-defined functions in the example. Check how the vectorized loop dispatches calc_A for quarter_angle and verify the behavior for Int16 and Int32 inputs. Done means documenting the required method definitions or confirming the supported dispatch pattern.

Written by the indexing model from the issue text.