tree-vrp.c (zero_nonzero_bits_from_vr): Make sure to always return true for constant integer ranges.

2011-08-05  Richard Guenther  <rguenther@suse.de>

	* tree-vrp.c (zero_nonzero_bits_from_vr): Make sure to always
	return true for constant integer ranges.
	(extract_range_from_binary_expr_1): Simplify BIT_AND_EXPR and
	BIT_IOR_EXPR handling.

	* gcc.dg/tree-ssa/vrp51.c: Disable CCP.
	* gcc.dg/tree-ssa/vrp52.c: Likewise.
	* gcc.dg/tree-ssa/vrp53.c: Likewise.

From-SVN: r177423