* Re: splitting before sched2
1998-04-04 16:52 splitting before sched2 Richard Henderson
@ 1998-04-04 14:20 ` Jeffrey A Law
1998-04-04 17:48 ` Richard Henderson
0 siblings, 1 reply; 5+ messages in thread
From: Jeffrey A Law @ 1998-04-04 14:20 UTC (permalink / raw)
To: Richard Henderson; +Cc: egcs
In message < 19980404120552.48484@dot.cygnus.com >you write:
> On Alpha at least there are a number of splits that are only enabled
> after reload is complete. I could have sworn other machines did this
> as well. My problem is that Haifa only tries splitting once, usually
> before reload.
Some machines do post reload splitting to help delay slot filling.
Recently (within the last year?) Joern added post reload splitting
to the old scheduler. I thought I had merged up all the changes
to the old scheduler into hafia, but I must have missed that one.
/* It is probably not worthwhile to try to split again in the
second pass. However, if flag_schedule_insns is not set,
the first and only (if any) scheduling pass is after reload. */
if (reload_completed == 0 || ! flag_schedule_insns)
I might argue that always splitting after reload would be a good
thing -- it would help some of the older PA7000 series machines
and there's also a case where it would help the PA8000 series.
My vote would be to unconditionally split after reload for both
schedulers.
jeff
^ permalink raw reply [flat|nested] 5+ messages in thread
* splitting before sched2
@ 1998-04-04 16:52 Richard Henderson
1998-04-04 14:20 ` Jeffrey A Law
0 siblings, 1 reply; 5+ messages in thread
From: Richard Henderson @ 1998-04-04 16:52 UTC (permalink / raw)
To: law, egcs
On Alpha at least there are a number of splits that are only enabled
after reload is complete. I could have sworn other machines did this
as well. My problem is that Haifa only tries splitting once, usually
before reload.
The question is, should we just remove/disable the test, or should we
come up with some genconfig test that determines if the second pass is
necessary. Possibly by seeing if any predicate contains the string
"reload".
r~
Index: haifa-sched.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/haifa-sched.c,v
retrieving revision 1.34
diff -c -p -d -r1.34 haifa-sched.c
*** haifa-sched.c 1998/03/28 23:45:08 1.34
--- haifa-sched.c 1998/04/04 19:58:04
*************** split_block_insns (b)
*** 8278,8284 ****
/* It is probably not worthwhile to try to split again in
the second pass. However, if flag_schedule_insns is not set,
the first and only (if any) scheduling pass is after reload. */
! if (reload_completed == 0 || ! flag_schedule_insns)
{
rtx last, first = PREV_INSN (insn);
rtx notes = REG_NOTES (insn);
--- 8278,8286 ----
/* It is probably not worthwhile to try to split again in
the second pass. However, if flag_schedule_insns is not set,
the first and only (if any) scheduling pass is after reload. */
! /* ??? Well, no, there are on some machines certain splits that are
! enabled *only* after reload is complete. */
! if (1 || reload_completed == 0 || ! flag_schedule_insns)
{
rtx last, first = PREV_INSN (insn);
rtx notes = REG_NOTES (insn);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: splitting before sched2
1998-04-04 14:20 ` Jeffrey A Law
@ 1998-04-04 17:48 ` Richard Henderson
1998-04-05 14:00 ` Joern Rennecke
0 siblings, 1 reply; 5+ messages in thread
From: Richard Henderson @ 1998-04-04 17:48 UTC (permalink / raw)
To: law; +Cc: Richard Henderson, egcs
> My vote would be to unconditionally split after reload for both
> schedulers.
Ok, done.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: splitting before sched2
1998-04-04 17:48 ` Richard Henderson
@ 1998-04-05 14:00 ` Joern Rennecke
1998-04-05 17:27 ` Richard Henderson
0 siblings, 1 reply; 5+ messages in thread
From: Joern Rennecke @ 1998-04-05 14:00 UTC (permalink / raw)
To: rth; +Cc: law, rth, egcs
> > My vote would be to unconditionally split after reload for both
> > schedulers.
>
> Ok, done.
IIRC there were some problems with the old scheduler when post-reload
splitting was first enabled. In particular with reg notes it couldn't
find the proper home for. It might be worth to check that the
ports with post-reload spilts still bootstrap & check OK with haifa.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: splitting before sched2
1998-04-05 14:00 ` Joern Rennecke
@ 1998-04-05 17:27 ` Richard Henderson
0 siblings, 0 replies; 5+ messages in thread
From: Richard Henderson @ 1998-04-05 17:27 UTC (permalink / raw)
To: Joern Rennecke; +Cc: rth, law, egcs
On Sun, Apr 05, 1998 at 10:00:01PM +0100, Joern Rennecke wrote:
> It might be worth to check that the
> ports with post-reload spilts still bootstrap & check OK with haifa.
At least Alpha and Sparc do, though they don't have really very many
post-reload splits. Which do you have in mind?
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~1998-04-05 17:27 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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1998-04-04 16:52 splitting before sched2 Richard Henderson
1998-04-04 14:20 ` Jeffrey A Law
1998-04-04 17:48 ` Richard Henderson
1998-04-05 14:00 ` Joern Rennecke
1998-04-05 17:27 ` Richard Henderson
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