+/// ReleasePred - Decrement the NumSuccsLeft count of a predecessor. When
+/// NumSuccsLeft reaches zero, release the predecessor node.
+///
+/// FIXME: Adjust PredSU height based on MinLatency.
+void ScheduleDAGMI::releasePred(SUnit *SU, SDep *PredEdge) {
+ SUnit *PredSU = PredEdge->getSUnit();
+
+#ifndef NDEBUG
+ if (PredSU->NumSuccsLeft == 0) {
+ dbgs() << "*** Scheduling failed! ***\n";
+ PredSU->dump(this);
+ dbgs() << " has been released too many times!\n";
+ llvm_unreachable(0);
+ }
+#endif
+ --PredSU->NumSuccsLeft;
+ if (PredSU->NumSuccsLeft == 0 && PredSU != &EntrySU)
+ SchedImpl->releaseBottomNode(PredSU);
+}
+
+/// releasePredecessors - Call releasePred on each of SU's predecessors.
+void ScheduleDAGMI::releasePredecessors(SUnit *SU) {
+ for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
+ I != E; ++I) {
+ releasePred(SU, &*I);
+ }
+}
+
+void ScheduleDAGMI::moveInstruction(MachineInstr *MI,
+ MachineBasicBlock::iterator InsertPos) {
+ // Advance RegionBegin if the first instruction moves down.
+ if (&*RegionBegin == MI)
+ ++RegionBegin;
+
+ // Update the instruction stream.
+ BB->splice(InsertPos, BB, MI);
+
+ // Update LiveIntervals
+ LIS->handleMove(MI);
+
+ // Recede RegionBegin if an instruction moves above the first.
+ if (RegionBegin == InsertPos)
+ RegionBegin = MI;
+}
+
+bool ScheduleDAGMI::checkSchedLimit() {
+#ifndef NDEBUG
+ if (NumInstrsScheduled == MISchedCutoff && MISchedCutoff != ~0U) {
+ CurrentTop = CurrentBottom;
+ return false;
+ }
+ ++NumInstrsScheduled;
+#endif
+ return true;
+}
+
+/// enterRegion - Called back from MachineScheduler::runOnMachineFunction after
+/// crossing a scheduling boundary. [begin, end) includes all instructions in
+/// the region, including the boundary itself and single-instruction regions
+/// that don't get scheduled.
+void ScheduleDAGMI::enterRegion(MachineBasicBlock *bb,
+ MachineBasicBlock::iterator begin,
+ MachineBasicBlock::iterator end,
+ unsigned endcount)
+{
+ ScheduleDAGInstrs::enterRegion(bb, begin, end, endcount);
+
+ // For convenience remember the end of the liveness region.
+ LiveRegionEnd =
+ (RegionEnd == bb->end()) ? RegionEnd : llvm::next(RegionEnd);
+}
+
+// Setup the register pressure trackers for the top scheduled top and bottom
+// scheduled regions.
+void ScheduleDAGMI::initRegPressure() {
+ TopRPTracker.init(&MF, RegClassInfo, LIS, BB, RegionBegin);
+ BotRPTracker.init(&MF, RegClassInfo, LIS, BB, LiveRegionEnd);
+
+ // Close the RPTracker to finalize live ins.
+ RPTracker.closeRegion();
+
+ DEBUG(RPTracker.getPressure().dump(TRI));
+
+ // Initialize the live ins and live outs.
+ TopRPTracker.addLiveRegs(RPTracker.getPressure().LiveInRegs);
+ BotRPTracker.addLiveRegs(RPTracker.getPressure().LiveOutRegs);
+
+ // Close one end of the tracker so we can call
+ // getMaxUpward/DownwardPressureDelta before advancing across any
+ // instructions. This converts currently live regs into live ins/outs.
+ TopRPTracker.closeTop();
+ BotRPTracker.closeBottom();
+
+ // Account for liveness generated by the region boundary.
+ if (LiveRegionEnd != RegionEnd)
+ BotRPTracker.recede();
+
+ assert(BotRPTracker.getPos() == RegionEnd && "Can't find the region bottom");
+
+ // Cache the list of excess pressure sets in this region. This will also track
+ // the max pressure in the scheduled code for these sets.
+ RegionCriticalPSets.clear();
+ std::vector<unsigned> RegionPressure = RPTracker.getPressure().MaxSetPressure;
+ for (unsigned i = 0, e = RegionPressure.size(); i < e; ++i) {
+ unsigned Limit = TRI->getRegPressureSetLimit(i);
+ DEBUG(dbgs() << TRI->getRegPressureSetName(i)
+ << "Limit " << Limit
+ << " Actual " << RegionPressure[i] << "\n");
+ if (RegionPressure[i] > Limit)
+ RegionCriticalPSets.push_back(PressureElement(i, 0));
+ }
+ DEBUG(dbgs() << "Excess PSets: ";
+ for (unsigned i = 0, e = RegionCriticalPSets.size(); i != e; ++i)
+ dbgs() << TRI->getRegPressureSetName(
+ RegionCriticalPSets[i].PSetID) << " ";
+ dbgs() << "\n");
+}
+
+// FIXME: When the pressure tracker deals in pressure differences then we won't
+// iterate over all RegionCriticalPSets[i].
+void ScheduleDAGMI::
+updateScheduledPressure(std::vector<unsigned> NewMaxPressure) {
+ for (unsigned i = 0, e = RegionCriticalPSets.size(); i < e; ++i) {
+ unsigned ID = RegionCriticalPSets[i].PSetID;
+ int &MaxUnits = RegionCriticalPSets[i].UnitIncrease;
+ if ((int)NewMaxPressure[ID] > MaxUnits)
+ MaxUnits = NewMaxPressure[ID];
+ }
+}
+
+/// schedule - Called back from MachineScheduler::runOnMachineFunction
+/// after setting up the current scheduling region. [RegionBegin, RegionEnd)
+/// only includes instructions that have DAG nodes, not scheduling boundaries.
+///
+/// This is a skeletal driver, with all the functionality pushed into helpers,
+/// so that it can be easilly extended by experimental schedulers. Generally,
+/// implementing MachineSchedStrategy should be sufficient to implement a new
+/// scheduling algorithm. However, if a scheduler further subclasses
+/// ScheduleDAGMI then it will want to override this virtual method in order to
+/// update any specialized state.
+void ScheduleDAGMI::schedule() {
+ buildDAGWithRegPressure();
+
+ postprocessDAG();