[PATCH][DAGCombiner] Teach the DAGCombiner how to fold sext/aext/zext of constant build_vectors.

[Nadav Rotem]

Hi Andrea, 

The patch LGTM. 

Thanks,
Nadav

On Jan 27, 2014, at 5:27 AM, Andrea Di Biagio <andrea.dibiagio at gmail.com> wrote:

> <patch.diff>