Integrate that for IPA ICF.

Integrate that for IPA ICF.

2019-10-30  Martin Liska  <mliska@suse.cz>

	* ipa-icf-gimple.c (func_checker::hash_operand): New.
	(func_checker::compare_cst_or_decl): Remove handling
	of FIELD_DECL.
	(func_checker::compare_operand): Transform to ...
	(func_checker::operand_equal_p): ... this.
	* ipa-icf-gimple.h (class func_checker): Add
	operand_equal_p and hash_operand.
	* ipa-icf.c (sem_function::equals_private): Fix
	pushing and popping of cfun.

From-SVN: r277615