Add inbounds annotation in map! computation

[YingboMa]

using BenchmarkTools

function foo!(a, b, c, d, e)
    map!((b, c, d, e) -> b + 0.1 * (0.2c + 0.3d + 0.4e), a, b, c, d, e)
end

a,b,c,d,e=(ones(1000) for i in 1:5)
@btime foo!($a, $b, $c, $d, $e);
# Master: 1.753 μs (1 allocation: 48 bytes)
# PR: 347.575 ns (1 allocation: 48 bytes)

If I put @_propagate_inbounds_meta in map_n!, the map! function will be a lot slower

julia> @btime foo!($a, $b, $c, $d, $e);
  583.367 ns (1 allocation: 48 bytes)

.

[nalimilan]

Thanks. I'd say we should merge the PR without the FIXME part for now, we can always figure out later why adding the @_propagate_inbounds_meta makes things (slightly) slower. As a first contribution, map_n! was introduced by @JeffBezanson in f4ed999, making it a separate function from map!, probably because it was faster for a reason that escapes me. So it's not completely surprising that inlining it makes things slower.

[YingboMa]

Bump

[KristofferC]

@nanosoldier runbenchmarks(ALL, vs = ":master")

[nanosoldier]

Your benchmark job has completed - possible performance regressions were detected. A full report can be found here. cc @ararslan

[YingboMa]

The regression seems to be noise.