getting auto-vectorization with gcc?
<p>In the context of evaluating negative-log-likelihoods, I have to
perform a bunch of  operations that could benefit from vectorization</p>

<p>0)  for (i = 1...n) {  a[i] = 0; }      /// but this I think</p>

<p>std::fill( a.begin(), a.end(), 0 ) is already optimal</p>

<p>1)  for (i = 1...n) {  a[i] += b * c[i]; }</p>

<p>2)  sum = 0; for (i = 1 .. n) { sum += a[i] * log( b[i] / c ); }</p>

<p>do you know if there's any hope to get gcc 434 to do
auto-vectorization, and how should I code the loop to help him (e.g.
using indices vs using iterators, should I break up (2) in simpler
loops, ...)
up to now I'm using doubles, have to check if I can move to floats at
least for (1).</p>
