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 
setTargetOccupancy(unsigned Occ)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
113