[llvm] r189989 - mi-sched: Reuse an invalid HazardRecognizer to save compile time.

[Andrew Trick]

Author: atrick
Date: Wed Sep  4 16:00:05 2013
New Revision: 189989

URL: http://llvm.org/viewvc/llvm-project?rev=189989&view=rev
Log:
mi-sched: Reuse an invalid HazardRecognizer to save compile time.

Modified:
    llvm/trunk/lib/CodeGen/MachineScheduler.cpp

Modified: llvm/trunk/lib/CodeGen/MachineScheduler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineScheduler.cpp?rev=189989&r1=189988&r2=189989&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineScheduler.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineScheduler.cpp Wed Sep  4 16:00:05 2013
@@ -1469,13 +1469,16 @@ public:
 
     void reset() {
       // A new HazardRec is created for each DAG and owned by SchedBoundary.
-      delete HazardRec;
-
+      // Detroying and reconstructing it is very expensive though. So keep
+      // invalid, placeholder HazardRecs.
+      if (HazardRec && HazardRec->isEnabled()) {
+        delete HazardRec;
+        HazardRec = 0;
+      }
       Available.clear();
       Pending.clear();
       CheckPending = false;
       NextSUs.clear();
-      HazardRec = 0;
       CurrCycle = 0;
       CurrMOps = 0;
       MinReadyCycle = UINT_MAX;
@@ -1681,9 +1684,14 @@ void ConvergingScheduler::initialize(Sch
   // are disabled, then these HazardRecs will be disabled.
   const InstrItineraryData *Itin = SchedModel->getInstrItineraries();
   const TargetMachine &TM = DAG->MF.getTarget();
-  Top.HazardRec = TM.getInstrInfo()->CreateTargetMIHazardRecognizer(Itin, DAG);
-  Bot.HazardRec = TM.getInstrInfo()->CreateTargetMIHazardRecognizer(Itin, DAG);
-
+  if (!Top.HazardRec) {
+    Top.HazardRec =
+      TM.getInstrInfo()->CreateTargetMIHazardRecognizer(Itin, DAG);
+  }
+  if (!Bot.HazardRec) {
+    Bot.HazardRec =
+      TM.getInstrInfo()->CreateTargetMIHazardRecognizer(Itin, DAG);
+  }
   assert((!ForceTopDown || !ForceBottomUp) &&
          "-misched-topdown incompatible with -misched-bottomup");
 }