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

[Benjamin Kramer]

On 04.09.2013, at 23:00, Andrew Trick <atrick at apple.com> wrote:

> 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

Typo: Detroying.

- Ben
> +      // 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");
> }
> 
> 
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