i965: Eliminate dead code more aggressively.

If an instruction writes reg but nothing later uses it, then we don't
need to bother doing it.  Before, we were just killing code that was
never read after it was ever written.

This removes many interpolation instructions for attributes with only
a few comopnents used.  Improves nexuiz high-settings performance .46%
+/- .12% (n=3) on my Ironlake.

0 files changed, 0 insertions, 0 deletions