tree-vrp.c (zero_nonzero_bits_from_vr): Also return precise information for ranges with only negative values.

2011-08-09  Richard Guenther  <rguenther@suse.de>

	* tree-vrp.c (zero_nonzero_bits_from_vr): Also return precise
	information for ranges with only negative values.
	(extract_range_from_binary_expr_1): Adjust BIT_IOR_EXPR and
	BIT_AND_EXPR handling to handle ranges with negative values.

	* gcc.dg/tree-ssa/vrp57.c: Disable CCP.
	* gcc.dg/tree-ssa/vrp60.c: New testcase.
	* gcc.dg/tree-ssa/vrp61.c: Likewise.
	* gcc.dg/tree-ssa/vrp62.c: Likewise.

From-SVN: r177597