re PR ipa/60315 (template constructor switch optimization)

re PR ipa/60315 (template constructor switch optimization)

	PR ipa/60315
	* cif-code.def (UNREACHABLE) New code.
	* ipa-inline.c (inline_small_functions): Skip edges to __builtlin_unreachable.
	(estimate_edge_growth): Allow edges to __builtlin_unreachable.
	* ipa-inline-analysis.c (edge_set_predicate): Redirect edges with false
	predicate to __bulitin_unreachable.
	(set_cond_stmt_execution_predicate): Fix issue when invert_tree_comparison
	returns ERROR_MARK.
	* ipa-pure-const.c (propagate_pure_const, propagate_nothrow): Do not
	propagate to inline clones.
	* cgraph.c (verify_edge_corresponds_to_fndecl): Allow redirection
	to unreachable.
	* ipa-cp.c (create_specialized_node): Be ready for new node to appear.
	* cgraphclones.c (cgraph_clone_node): If call destination is already
	ureachable, do not redirect it back.
	* tree-inline.c (fold_marked_statements): Hanlde calls becoming
	unreachable.

From-SVN: r208831