* cgraph.h (verify_symtab, verify_symtab_node, verify_symtab_base):
	Declare.
	* cgraphunit.c (verify_cgraph_node): Verify symtab base; do not verify 
	cgraph hash and same comdat groups.
	(cgraph_optimize); Verify symbol table.
	* ipa.c (cgraph_remove_unreachable_nodes): Verify symbol table.
	(dissolve_same_comdat_group_list): Work on symtab nodes.
	(function_and_variable_visibility): Dissolve variable same comdat group
	lists, too.
	* symtab.c: Include timevar.h
	(verify_symtab_base, verify_symtab_node, verify_symtab): New functions.

From-SVN: r186578