Fix PR ipa/64693

	PR ipa/64693
	* ipa-icf.c (symbol_compare_collection::symbol_compare_collection): New.
	(sem_item_optimizer::subdivide_classes_by_sensitive_refs): New function.
	(sem_item_optimizer::process_cong_reduction): Include division by
	sensitive references.
	* ipa-icf.h (struct symbol_compare_hashmap_traits): New class.
	* ipa-ref.c (ipa_ref::address_matters_p): New function.
	* ipa-ref.h (ipa_ref::address_matters_p): Likewise.
	* g++.dg/ipa/pr64146.C: Update expected results.
	* gcc.dg/ipa/ipa-icf-26.c: Update test.
	* gcc.dg/ipa/ipa-icf-33.c: Remove redundant line.
	* gcc.dg/ipa/ipa-icf-34.c: New test.

Co-Authored-By: Jan Hubicka <hubicka@ucw.cz>

From-SVN: r221031