Is there a fast product operation for PackedArrays?

Question

In Mathematica a vector (or rectangular array) containing all machine size integers or floats may be stored in a packed array. These objects take less memory, and some operatio

Answer 1

Simon's method is fast, but it fails on negative values. Combining it with his answer to my other question, here is a fast solution that handles negatives. Thanks, Simon.

Function

f = (-1)^(-1 /. Rule @@@ Tally@Sign@# /. -1 -> 0) * Exp@Total@Log@Abs@# &;

---

Testing

lst = RandomReal[{-50, 50}, 5000000];

Times @@ lst // Timing
f@lst // Timing

lst = Developer`FromPackedArray[lst];

Times @@ lst // Timing
f@lst // Timing

---

{0.844, -4.42943661963*10^6323240}

{0.062, -4.4294366*10^6323240}

{0.64, -4.42943661963*10^6323240}

{0.203, -4.4294366*10^6323240}