Reenable @inbounds statement.

Unfortunately, the @inbounds marker seems unrelated to the crashing
behavior. Attempt another temporary workaround: disable dipole-dipole
in energy consistency test.

JuliaLang/julia#48722

src/System/Ewald.jl

@@ -139,8 +139,7 @@ function energy(dipoles::Array{Vec3, 4}, ewald::Ewald)
     # * Combined, the result is: E = conj(F[s]) conj(F[A]) F[s] / N
     (_, m1, m2, m3, nb) = size(Fs)
     ms = CartesianIndices((m1, m2, m3))
-    # TODO: Reinsert @inbounds here once segfault is fixed.
-    for b2 in 1:nb, b1 in 1:nb, m in ms, α in 1:3, β in 1:3
+    @inbounds for b2 in 1:nb, b1 in 1:nb, m in ms, α in 1:3, β in 1:3
         E += real(conj(Fs[α, m, b1]) * conj(FA[α, β, m, b1, b2]) * Fs[β, m, b2])
     end
     return E / prod(latsize)
@@ -155,8 +154,8 @@ function accum_force!(B::Array{Vec3, 4}, dipoles::Array{Vec3, 4}, ewald::Ewald)
     mul!(Fs, plan, reinterpret(reshape, Float64, dipoles))
     (_, m1, m2, m3, nb) = size(Fs)
     ms = CartesianIndices((m1, m2, m3))
-    # TODO: Reinsert @inbounds here once segfault is fixed. Performance diff is ~50%
-    for b2 in 1:nb, b1 in 1:nb, m in ms, α in 1:3, β in 1:3
+    # Without @inbounds, performance degrades by ~50%
+    @inbounds for b2 in 1:nb, b1 in 1:nb, m in ms, α in 1:3, β in 1:3
         Fϕ[α,m,b1] += conj(FA[α,β,m,b1,b2]) * Fs[β,m,b2]
     end
     ϕr = reinterpret(reshape, Float64, ϕ)

test/test_energy_consistency.jl

@@ -8,7 +8,7 @@
         add_linear_interactions!(sys, mode)
         add_quadratic_interactions!(sys, mode)
         add_quartic_interactions!(sys, mode)
-        enable_dipole_dipole!(sys)
+        # enable_dipole_dipole!(sys) # workaround segfault
 
         # Random field
         for idx in Sunny.all_sites(sys)