2008-08-20  Richard Guenther  <rguenther@suse.de>

	* tree-vrp.c (op_with_constant_singleton_value_range): New function.
	(extract_range_from_binary_expr): Fall back to constant propagation.
	(extract_range_from_unary_expr): Likewise.

	* gcc.dg/tree-ssa/pr21829.c: Scan optimized and cddce2 dumps
	instead of phicprop2.  Make sure all is fine after cddce2,
	add an XFAILed scan for merging the two remaining ifs.

From-SVN: r139326