tree-ssa-sccvn.h (struct vn_ssa_aux): Make the most accessed field (valnum) the first in the struct.

2008-01-10  Steven Bosscher  <stevenb.gcc@gmail.com>

	* tree-ssa-sccvn.h (struct vn_ssa_aux): Make the most accessed
	field (valnum) the first in the struct.  Replace bools with
	unit bit fields.

From-SVN: r131444