lib/Target/AMDGPU/GCNSchedStrategy.h

   1 //===-- GCNSchedStrategy.h - GCN Scheduler Strategy -*- C++ -*-------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 /// \file
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_TARGET_AMDGPU_GCNSCHEDSTRATEGY_H
  15 #define LLVM_LIB_TARGET_AMDGPU_GCNSCHEDSTRATEGY_H
  16
  17 #include "GCNRegPressure.h"
  18 #include "llvm/CodeGen/MachineScheduler.h"
  19
  20 namespace llvm {
  21
  22 class SIMachineFunctionInfo;
  23 class SIRegisterInfo;
  24 class GCNSubtarget;
  25
  26 /// This is a minimal scheduler strategy.  The main difference between this
  27 /// and the GenericScheduler is that GCNSchedStrategy uses different
  28 /// heuristics to determine excess/critical pressure sets.  Its goal is to
  29 /// maximize kernel occupancy (i.e. maximum number of waves per simd).
  30 class GCNMaxOccupancySchedStrategy : public GenericScheduler {
  31   friend class GCNScheduleDAGMILive;
  32
  33   SUnit *pickNodeBidirectional(bool &IsTopNode);
  34
  35   void pickNodeFromQueue(SchedBoundary &Zone, const CandPolicy &ZonePolicy,
  36                          const RegPressureTracker &RPTracker,
  37                          SchedCandidate &Cand);
  38
  39   void initCandidate(SchedCandidate &Cand, SUnit *SU,
  40                      bool AtTop, const RegPressureTracker &RPTracker,
  41                      const SIRegisterInfo *SRI,
  42                      unsigned SGPRPressure, unsigned VGPRPressure);
  43
  44   unsigned SGPRExcessLimit;
  45   unsigned VGPRExcessLimit;
  46   unsigned SGPRCriticalLimit;
  47   unsigned VGPRCriticalLimit;
  48
  49   unsigned TargetOccupancy;
  50
  51   MachineFunction *MF;
  52
  53 public:
  54   GCNMaxOccupancySchedStrategy(const MachineSchedContext *C);
  55
  56   SUnit *pickNode(bool &IsTopNode) override;
  57
  58   void initialize(ScheduleDAGMI *DAG) override;
  59
  60   void setTargetOccupancy(unsigned Occ) { TargetOccupancy = Occ; }
  61 };
  62
  63 class GCNScheduleDAGMILive : public ScheduleDAGMILive {
  64
  65   const GCNSubtarget &ST;
  66
  67   SIMachineFunctionInfo &MFI;
  68
  69   // Occupancy target at the beginning of function scheduling cycle.
  70   unsigned StartingOccupancy;
  71
  72   // Minimal real occupancy recorder for the function.
  73   unsigned MinOccupancy;
  74
  75   // Scheduling stage number.
  76   unsigned Stage;
  77
  78   // Current region index.
  79   size_t RegionIdx;
  80
  81   // Vecor of regions recorder for later rescheduling
  82   SmallVector<std::pair<MachineBasicBlock::iterator,
  83                         MachineBasicBlock::iterator>, 32> Regions;
  84
  85   // Region live-in cache.
  86   SmallVector<GCNRPTracker::LiveRegSet, 32> LiveIns;
  87
  88   // Region pressure cache.
  89   SmallVector<GCNRegPressure, 32> Pressure;
  90
  91   // Temporary basic block live-in cache.
  92   DenseMap<const MachineBasicBlock*, GCNRPTracker::LiveRegSet> MBBLiveIns;
  93
  94   // Return current region pressure.
  95   GCNRegPressure getRealRegPressure() const;
  96
  97   // Compute and cache live-ins and pressure for all regions in block.
  98   void computeBlockPressure(const MachineBasicBlock *MBB);
  99
 100
 101 public:
 102   GCNScheduleDAGMILive(MachineSchedContext *C,
 103                        std::unique_ptr<MachineSchedStrategy> S);
 104
 105   void schedule() override;
 106
 107   void finalizeSchedule() override;
 108 };
 109
 110 } // End namespace llvm
 111
 112 #endif // GCNSCHEDSTRATEGY_H