Base.Math.JuliaLibm.log1p infinite recursion

[tpapp]

The function Base.Math.JuliaLibm.log1p (a more accurate, and usually faster version of Base.log1p) goes into infinite recursion when used with ForwardDiff.Duals. MWE:

julia> using ForwardDiff

julia> Base.Math.JuliaLibm.log1p(ForwardDiff.Dual(1.0,1.0))
VERSION
ERROR: StackOverflowError:
Stacktrace:
 [1] log1p(::ForwardDiff.Dual{Void,Float64,1}) at ./special/log.jl:395 (repeats 80000 times)

julia> VERSION
v"0.6.0"

julia> Pkg.status("ForwardDiff")
 - ForwardDiff                   0.5.0

[jrevels]

Looks like Base.Math.JuliaLibm.log1p(x::Real) just calls Base.Math.JuliaLibm.log1p(float(x)), which basically guarantees infinite recursion in the general case (e.g. T = typeof(float(x)); T <: Real && !(T <: Float64) && !(T <: Float32)).

Easiest solution would be to add a rule for Base.Math.JuliaLibm.log1p to DiffRules.

[tpapp]

Closed by JuliaDiff/DiffRules.jl#8.