PR middle-end/28071

PR middle-end/28071
* sched-int.h (struct deps): Split field 'pending_lists_length' into
'pending_read_list_length' and 'pending_write_list_length'.  Update
comment.
* sched-deps.c (add_insn_mem_dependence): Change signature.  Update
to handle two length counters instead of one.  Update all uses.
(flush_pending_lists, sched_analyze_1, init_deps): Update to handle
two length counters instead of one.
* sched-rgn.c (propagate_deps): Update to handle two length counters
instead of one.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@123874 138bc75d-0d04-0410-961f-82ee72b054a4