2012-10-08  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/54825
	* tree-ssa-sccvn.c (vn_nary_length_from_stmt): Handle BIT_FIELD_REF.
	(init_vn_nary_op_from_stmt): Likewise.
	* tree-ssa-pre.c (compute_avail): Use vn_nary_op_lookup_stmt.
	* tree-ssa-sccvn.h (sizeof_vn_nary_op): Avoid overflow.

From-SVN: r192205