From: Andrew Trick <atrick@apple.com>
Date: Fri, 6 Sep 2013 17:32:36 +0000 (+0000)
Subject: mi-sched: Reorder Cyclicpath (latency) and CriticalMax (pressure) heuristics.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f9c2fa8341d4b7fe64ccd7beb5696d4a9934f5e9;p=oota-llvm.git

mi-sched: Reorder Cyclicpath (latency) and CriticalMax (pressure) heuristics.

The latency based scheduling could induce spills in some cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190177 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index b854a13f0aa..7d957b5f302 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -2469,16 +2469,16 @@ void ConvergingScheduler::tryCandidate(SchedCandidate &Cand,
                                                TryCand, Cand, RegExcess))
     return;
 
-  // For loops that are acyclic path limited, aggressively schedule for latency.
-  if (Rem.IsAcyclicLatencyLimited && tryLatency(TryCand, Cand, Zone))
-    return;
-
   // Avoid increasing the max critical pressure in the scheduled region.
   if (DAG->isTrackingPressure() && tryPressure(TryCand.RPDelta.CriticalMax,
                                                Cand.RPDelta.CriticalMax,
                                                TryCand, Cand, RegCritical))
     return;
 
+  // For loops that are acyclic path limited, aggressively schedule for latency.
+  if (Rem.IsAcyclicLatencyLimited && tryLatency(TryCand, Cand, Zone))
+    return;
+
   // Keep clustered nodes together to encourage downstream peephole
   // optimizations which may reduce resource requirements.
   //