Re: Fwd: [PATCH] Scheduling result adjustment to enable macro-fusion

[Jeff Law <law at redhat dot com>]

On 11/26/13 12:33, Wei Mi wrote:
> On Mon, Nov 25, 2013 at 2:12 PM, Jeff Law <law@redhat.com> wrote:
> > > Doing the cleanup at the end of BB could ensure all the groups
> > > inserted for macrofusion will be cleaned. For groups not at the end of
> > > a block, no matter whether they are cleaned up or not, nothing will
> > > happen because other passes will not mess up those groups -- you said
> > > cc0-setter/cc0-user was such a case. Is it call group a different
> > > case?
> >
> > True, it would be safe, but it seems inconsistent and confusing that some
> > SCHED_GROUP_P references would be purged and others remain.
> >
> > Given SCHED_GROUP_P is to used strictly in the scheduler ISTM that we should
> > be wiping it as we leave and that our RTL checkers ought to be verifying
> > there are no insns with SCHED_GROUP_P left on.
>
> How about add a verifier TODO_verify_sched_group_flag similar as
> TODO_verify_rtl_sharing, and add the verifier in the todo lists of all
> the scheduling passes.
>
> > > For sched1 and sched2, we can do that. Actually, I find it has been
> > > done in move_insn when commit_schedule. But for modulo scheduling, I
> > > havn't found a good place to do it.
> >
> > Well, that's where I'd suggest focusing attention.
> >
> > jeff
>
> After looking it carefully, even for sched1 and sched2, it is not ok
> to depend on move_insn in commit_schedule to clean up all the
> SCHED_GROUP_P, suppose a block is decided not to be scheduled by
> dbg_cnt, then SCHED_GROUP_P inside the block will not be cleaned.
> It is even more difficult to find a place inside SMS scheduling to do
> the cleanup.
>
> Any suggestions?
Hmm, maybe attack from the other direction? -- could we clear 
SCHED_GROUP_P for each insn at the start of this loop in sched_analyze?

It's not as clean in the sense that SCHED_GROUP_P "escapes" the 
scheduler, but it might be an option.

   for (insn = head;; insn = NEXT_INSN (insn))
    {

      if (INSN_P (insn))
        {
          /* And initialize deps_lists.  */
          sd_init_insn (insn);
        }

      deps_analyze_insn (deps, insn);

      if (insn == tail)
        {
          if (sched_deps_info->use_cselib)
            cselib_finish ();
          return;
        }
    }
Jeff
>