From 28ebc89c413c042bf693d9ad6971f0fb5cca2f0f Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Thu, 10 May 2012 21:06:19 +0000
Subject: [PATCH] misched: tracing register pressure heuristics.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156575 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/MachineScheduler.cpp | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index b362708fce2..650fa5da88e 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -724,11 +724,28 @@ public:
       BotQueue.push(SU);
   }
 protected:
+#ifndef NDEBUG
+  void traceCandidate(const char *Label, unsigned QID, SUnit *SU,
+                      int RPDiff, unsigned PSetID);
+#endif
   bool pickNodeFromQueue(ReadyQ &Q, const RegPressureTracker &RPTracker,
                          SchedCandidate &Candidate);
 };
 } // namespace
 
+#ifndef NDEBUG
+void ConvergingScheduler::
+traceCandidate(const char *Label, unsigned QID, SUnit *SU,
+               int RPDiff, unsigned PSetID) {
+  dbgs() << Label << getQName(QID) << " ";
+  if (RPDiff)
+    dbgs() << TRI->getRegPressureSetName(PSetID) << ":" << RPDiff << " ";
+  else
+    dbgs() << "     ";
+  SU->dump(DAG);
+}
+#endif
+
 /// Pick the best candidate from the top queue.
 ///
 /// TODO: getMaxPressureDelta results can be mostly cached for each SUnit during
@@ -749,6 +766,8 @@ bool ConvergingScheduler::pickNodeFromQueue(ReadyQ &Q,
 
     // Avoid exceeding the target's limit.
     if (!Candidate.SU || RPDelta.ExcessUnits < Candidate.RPDelta.ExcessUnits) {
+      DEBUG(traceCandidate(Candidate.SU ? "PCAND" : "ACAND", Q.ID, *I,
+                           RPDelta.ExcessUnits, RPDelta.ExcessSetID));
       Candidate.SU = *I;
       Candidate.RPDelta = RPDelta;
       FoundCandidate = true;
@@ -759,15 +778,11 @@ bool ConvergingScheduler::pickNodeFromQueue(ReadyQ &Q,
 
     // Avoid increasing the max pressure.
     if (RPDelta.MaxUnitIncrease < Candidate.RPDelta.MaxUnitIncrease) {
+      DEBUG(traceCandidate("MCAND", Q.ID, *I,
+                           RPDelta.ExcessUnits, RPDelta.ExcessSetID));
       Candidate.SU = *I;
       Candidate.RPDelta = RPDelta;
       FoundCandidate = true;
-
-      DEBUG(dbgs() << "CAND " << getQName(Q.ID) << " ";
-            if (RPDelta.MaxUnitIncrease)
-              dbgs() << TRI->getRegPressureSetName(RPDelta.MaxSetID) << ":"
-                     << RPDelta.MaxUnitIncrease << " ";
-            (*I)->dump(DAG); dbgs() << "\n");
       continue;
     }
     if (RPDelta.MaxUnitIncrease > Candidate.RPDelta.MaxUnitIncrease)
@@ -780,6 +795,7 @@ bool ConvergingScheduler::pickNodeFromQueue(ReadyQ &Q,
 
     if ((Q.ID == TopQID && (*I)->NodeNum < Candidate.SU->NodeNum)
         || (Q.ID == BotQID && (*I)->NodeNum > Candidate.SU->NodeNum)) {
+      DEBUG(traceCandidate("NCAND", Q.ID, *I, 0, 0));
       Candidate.SU = *I;
       Candidate.RPDelta = RPDelta;
       FoundCandidate = true;
-- 
2.34.1