2012-01-05  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/51760
	* tree-ssa-ccp.c (likely_value): Drop UNDEFINED to CONSTANT,
	not VARYING.
	(bit_value_unop): Handle UNDEFINED operands.
	(bit_value_binop): Likewise.

	* gcc.dg/torture/pr51760.c: New testcase.

From-SVN: r182909