tree-ssa-ccp.c (valid_lattice_transition): Clarify comment about transition from invariant to known bits.

2012-07-19  Richard Guenther  <rguenther@suse.de>
	Eric Botcazou  <ebotcazou@adacore.com>

	* tree-ssa-ccp.c (valid_lattice_transition): Clarify comment
	about transition from invariant to known bits.
	(likely_value): Addresses with UNDEFINED components are
	UNDEFINED.

	* gnat.dg/loop_optimization11.adb: New testcase.
	* gnat.dg/loop_optimization11_pkg.ads: Likewise.

Co-Authored-By: Eric Botcazou <ebotcazou@adacore.com>

From-SVN: r189650