Speed up extrapolation by eliminating splat penalty

Author: timholy

src/extrapolation/extrapolation.jl

@@ -50,6 +50,7 @@ and indices. The heavy lifting is done by the `extrap_prep` function; see
 function getindex_impl{T,N,ITPT,IT,GT,ET}(etp::Type{Extrapolation{T,N,ITPT,IT,GT,ET}}, xs...)
     coords = [Symbol("xs_",d) for d in 1:N]
     quote
+        $(Expr(:meta, :inline))
         @nexprs $N d->(xs_d = xs[d])
         $(extrap_prep(ET, Val{N}()))
         etp.itp[$(coords...)]
@@ -66,6 +67,7 @@ checkbounds(::AbstractExtrapolation,I...) = nothing
 function gradient!_impl{T,N,ITPT,IT,GT,ET}(g, etp::Type{Extrapolation{T,N,ITPT,IT,GT,ET}}, xs...)
     coords = [Symbol("xs_", d) for d in 1:N]
     quote
+        $(Expr(:meta, :inline))
         @nexprs $N d->(xs_d = xs[d])
         $(extrap_prep(Val{:gradient}(), ET, Val{N}()))
         gradient!(g, etp.itp, $(coords...))