julia> function perf_sumlinear_view(A)
           s = zero(eltype(A))
           @inbounds @simd for I in 1:length(A)
               val = view(A, I)
               s += val[]
           end
           return s
       end
perf_sumlinear_view (generic function with 1 method)

julia> A = 1:1000000
1:1000000

julia> using BenchmarkTools

julia> @btime perf_sumlinear_view(A)
  110.620 μs (1 allocation: 16 bytes)
500000500000

julia> Base.firstindex(::UnitRange) = 1

julia> @btime perf_sumlinear_view(A)
  28.288 ns (1 allocation: 16 bytes)
500000500000