* tree-ssa-alias.h (pt_solution_singleton_or_null_p): Renamed from
pt_solution_singleton_p.
* tree-ssa-ccp.c (fold_builtin_alloca_with_align): Use renamed
pt_solution_singleton_or_null_p from pt_solution_singleton_p.
* tree-ssa-structalias.c (find_what_p_points_to): Preserve
pointer nonnull computed by VRP.
Also Conservatively set pt.null to 1.
(pt_solution_reset): Conservatively set pt.null to 1.
(pt_solution_singleton_or_null_p): Renamed from
pt_solution_singleton_p.
* tree-ssanames.h (set_ptr_nonnull): Declare.
(get_ptr_nonnull): Likewise.
* tree-ssanames.c (set_ptr_nonnull): New.
(get_ptr_nonnull): Likewise.
* tree-vrp.c (vrp_finalize): Set ptr that are nonnull.
(evrp_dom_walker::before_dom_children): Likewise.