* tree-predcom.c: (struct chain): Handle store-store chain in which
	stores for elimination only store loop invariant values.
	(execute_pred_commoning_chain): Ditto.
	(prepare_initializers_chain_store_elim): Ditto.
	(prepare_finalizers): Ditto.
	(is_inv_store_elimination_chain): New function.
	(initialize_root_vars_store_elim_1): New function.

From-SVN: r250670