Commit f9f78cf6 authored by Lorenzo Casalino's avatar Lorenzo Casalino Committed by Florian Hahn
Browse files

[MachineScheduler] improve reuse of 'releaseNode'method 

The 'SchedBoundary::releaseNode' is merely invoked for releasing the Top/Bottom root nodes.
However,  'SchedBoundary::releasePending' uses its same logic to check if the Pending queue
has any releasable SUnit.
It is possible to slightly modify the body of the two, allowing re-use of the former ('releaseNode')
in the latter.

Patch by Lorenzo Casalino <lorenzo.casalino93@gmail.com>

Reviewers: MatzeB, fhahn, atrick

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D65506
parent 11552433

llvm/include/llvm/CodeGen/MachineScheduler.h

+5 −4
Original line number Diff line number Diff line
@@ -757,7 +757,8 @@ public: 


  unsigned getOtherResourceCount(unsigned &OtherCritIdx);



  void releaseNode(SUnit *SU, unsigned ReadyCycle);

  template <bool InPQueue>

  void releaseNode(SUnit *SU, unsigned ReadyCycle, unsigned Idx = 0);



  void bumpCycle(unsigned NextCycle);
@@ -955,7 +956,7 @@ public: 
    if (SU->isScheduled)

      return;



    Top.releaseNode(SU, SU->TopReadyCycle);

    Top.releaseNode<false>(SU, SU->TopReadyCycle);

    TopCand.SU = nullptr;

  }
@@ -963,7 +964,7 @@ public: 
    if (SU->isScheduled)

      return;



    Bot.releaseNode(SU, SU->BotReadyCycle);

    Bot.releaseNode<false>(SU, SU->BotReadyCycle);

    BotCand.SU = nullptr;

  }
@@ -1043,7 +1044,7 @@ public: 
  void releaseTopNode(SUnit *SU) override {

    if (SU->isScheduled)

      return;

    Top.releaseNode(SU, SU->TopReadyCycle);

    Top.releaseNode<false>(SU, SU->TopReadyCycle);

  }



  // Only called for roots.

llvm/lib/CodeGen/MachineScheduler.cpp

+21 −17
Original line number Diff line number Diff line
@@ -2088,7 +2088,8 @@ getOtherResourceCount(unsigned &OtherCritIdx) { 
  return OtherCritCount;

}



void SchedBoundary::releaseNode(SUnit *SU, unsigned ReadyCycle) {

template <bool InPQueue>

void SchedBoundary::releaseNode(SUnit *SU, unsigned ReadyCycle, unsigned Idx) {

  assert(SU->getInstr() && "Scheduled SUnit must have instr");



#ifndef NDEBUG
@@ -2105,11 +2106,19 @@ void SchedBoundary::releaseNode(SUnit *SU, unsigned ReadyCycle) { 
  // Check for interlocks first. For the purpose of other heuristics, an

  // instruction that cannot issue appears as if it's not in the ReadyQueue.

  bool IsBuffered = SchedModel->getMicroOpBufferSize() != 0;

  if ((!IsBuffered && ReadyCycle > CurrCycle) || checkHazard(SU) ||

      Available.size() >= ReadyListLimit)

    Pending.push(SU);

  else

  bool HazardDetected = (!IsBuffered && ReadyCycle > CurrCycle) ||

                        checkHazard(SU) || (Available.size() >= ReadyListLimit);



  if (!HazardDetected) {

    Available.push(SU);



    if (InPQueue)

      Pending.remove(Pending.begin() + Idx);

    return;

  }



  if (!InPQueue)

    Pending.push(SU);

}



/// Move the boundary of scheduled code by one cycle.
@@ -2349,26 +2358,21 @@ void SchedBoundary::releasePending() { 


  // Check to see if any of the pending instructions are ready to issue.  If

  // so, add them to the available queue.

  bool IsBuffered = SchedModel->getMicroOpBufferSize() != 0;

  for (unsigned i = 0, e = Pending.size(); i != e; ++i) {

    SUnit *SU = *(Pending.begin()+i);

  for (unsigned I = 0, E = Pending.size(); I < E; ++I) {

    SUnit *SU = *(Pending.begin() + I);

    unsigned ReadyCycle = isTop() ? SU->TopReadyCycle : SU->BotReadyCycle;



    if (ReadyCycle < MinReadyCycle)

      MinReadyCycle = ReadyCycle;



    if (!IsBuffered && ReadyCycle > CurrCycle)

      continue;



    if (checkHazard(SU))

      continue;



    if (Available.size() >= ReadyListLimit)

      break;



    Available.push(SU);

    Pending.remove(Pending.begin()+i);

    --i; --e;

    releaseNode<true>(SU, ReadyCycle, I);

    if (E != Pending.size()) {

      --I;

      --E;

    }

  }

  CheckPending = false;

}