re PR debug/41535 (Broken var location info after scheduling)

PR debug/41535
* sched-deps.c (depl_on_debug_p): New.
(attach_dep_link): Reject debug deps before nondebug deps.
(add_to_deps_list): Insert debug deps after nondebug deps.
(sd_lists_empty_p): Stop at first nonempty list.  Disregard debug
deps.
(sd_add_dep): Do not reject debug deps.
(add_insn_mem_dependence): Don't count debug deps.
(remove_from_deps): Likewise.
(sched_analyze_2): Set up mem deps on debug insns.
(sched_analyze_insn): Record reg uses for deps on debug insns.
* haifa-sched.c (schedule_insn): Reset deferred debug insn.  Don't
try_ready nondebug insn after debug insn.
* ddg.c (create_ddg_dep_from_intra_loop_link,
create_ddg_dep_no_link): Don't reject debug deps.

From-SVN: r152927