diff --git a/julia/track_tbaa/gen.jl b/julia/track_tbaa/gen.jl
new file mode 100644
index 0000000..29e0d7a
--- /dev/null
+++ b/julia/track_tbaa/gen.jl
@@ -0,0 +1,19 @@
+#!/usr/bin/julia -f
+
+immutable Gen
+    iter::UnitRange{Int}
+end
+gen = Gen(1:10)
+function collect_to2!{T}(dest::AbstractArray{T}, itr)
+    i = 1
+    st = start(itr.iter)
+    while !done(itr.iter, st)
+        el, st = next(itr.iter, st)
+        @inbounds dest[i] = el
+        i += 1
+    end
+    return dest
+end
+# code_llvm(STDOUT, collect_to2!, Tuple{Vector{Float64},Gen}, false, true)
+@code_llvm collect_to2!(Vector{Float64}(10), gen)
+@show collect_to2!(Vector{Float64}(10), gen)