Insufficiently aggressive activity analysis

[wsmoses]

using Enzyme 

struct RHS_terms
    eta1::Vector{Float64}
    u_t::Vector{Float64} 
    eta_t::Vector{Float64}
end

@noinline function comp_u_v_eta_t(rhs) 
    Base.unsafe_copyto!(rhs.eta_t, 1, rhs.u_t, 1, 1)
    return nothing
end 

function advance(eta, rhs)

    @inbounds rhs.eta1[1] = @inbounds eta[1]

    comp_u_v_eta_t(rhs)

    @inbounds eta[1] = @inbounds rhs.eta_t[1]

    return nothing 

end

rhs_terms = RHS_terms(zeros(1), zeros(1), zeros(1))

u_v_eta = Float64[NaN]

Enzyme.API.printall!(true)
Enzyme.API.printactivity!(true)

ad_eta = zeros(1)

@show ad_eta
# Enzyme.API.runtimeActivity!(true)

autodiff(Reverse, advance, 
    Duplicated(u_v_eta, ad_eta),
    Const(rhs_terms), 
)
@show ad_eta

requires: EnzymeAD/Enzyme#1020