Fix for devirtualization dump functions

Fix for devirtualization dump functions

        * gimple.h (gimple_location_safe): New function introduced.
	* cgraphunit.c (walk_polymorphic_call_targets): Usage
	of gimple_location_safe replaces gimple_location.
	(gimple_fold_call): Likewise.
	* ipa-devirt.c (ipa_devirt): Likewise.
	* ipa-prop.c (ipa_make_edge_direct_to_target): Likewise.
	* ipa.c (walk_polymorphic_call_targets): Likewise.
	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): Likewise.

From-SVN: r212067