ipa-prop.c (remove_described_reference): Accept missing references, return false if that hppens, otherwise return true.

2013-09-05  Martin Jambor  <mjambor@suse.cz>

	* ipa-prop.c (remove_described_reference): Accept missing references,
	return false if that hppens, otherwise return true.
	(cgraph_node_for_jfunc): New function.
	(try_decrement_rdesc_refcount): Likewise.
	(try_make_edge_direct_simple_call): Use them.
	(ipa_edge_removal_hook): Remove references from rdescs.
	(ipa_edge_duplication_hook): Clone rdescs and their references
	when the new edge has the same caller as the old one.
	* cgraph.c (cgraph_resolve_speculation): Remove speculative
	reference before removing any edges.

testsuite/
	* g++.dg/ipa/remref-1.C: New test.
	* g++.dg/ipa/remref-2.C: Likewise.

From-SVN: r202281