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

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Submitter Alexander Monakov
Date Sept. 11, 2013, 4:41 p.m.
Message ID <alpine.LNX.2.00.1309112023220.2373@monopod.intra.ispras.ru>
Download mbox | patch
Permalink /patch/274340/
State New
Headers show

Comments

Alexander Monakov - Sept. 11, 2013, 4:41 p.m.
On Wed, 11 Sep 2013, Wei Mi wrote:

> I tried that and it caused some regressions, so I choosed to do
> chain_to_prev_insn another time in add_branch_dependences. There could
> be some dependence between those two functions.

(please don't top-post on this list)

In that case you can adjust 'last' in add_branch_dependences so that the
dependences pin the compare rather than the jump to the end, like this
(untested):


I'm also not a fan of adding two scheduler hooks and explicit handling in
sched-deps.c for this feature.  You probably could handle that with sched_init
hook entirely in the x86 backend (just loop over basic blocks and mark
suitable jumps with SCHED_GROUP_P), but on the other hand I can see an
argument that this might be useful in the future for other architectures.
Have you considered that?  What do other maintainers say?

Thanks.

Alexander

Patch

diff --git a/gcc/sched-rgn.c b/gcc/sched-rgn.c
index 2c971e2..a774d5d 100644
--- a/gcc/sched-rgn.c
+++ b/gcc/sched-rgn.c
@@ -2443,6 +2443,9 @@  add_branch_dependences (rtx head, rtx tail)
      cc0 setters remain at the end because they can't be moved away from
      their cc0 user.
 
+     Predecessors of SCHED_GROUP_P instructions that remain at the end also
+     remain at the end.
+
      COND_EXEC insns cannot be moved past a branch (see e.g. PR17808).
 
      Insns setting TARGET_CLASS_LIKELY_SPILLED_P registers (usually return
@@ -2465,6 +2468,7 @@  add_branch_dependences (rtx head, rtx tail)
 #endif
 		 || (!reload_completed
 		     && sets_likely_spilled (PATTERN (insn)))))
+	 || (last != 0 && SCHED_GROUP_P (last))
 	 || NOTE_P (insn))
     {
       if (!NOTE_P (insn))