1 //===-- GCNSchedStrategy.h - GCN Scheduler Strategy -*- C++ -*-------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 /// \file
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_AMDGPU_GCNSCHEDSTRATEGY_H
14 #define LLVM_LIB_TARGET_AMDGPU_GCNSCHEDSTRATEGY_H
15 
16 #include "GCNRegPressure.h"
17 #include "llvm/CodeGen/MachineScheduler.h"
18 
19 namespace llvm {
20 
21 class SIMachineFunctionInfo;
22 class SIRegisterInfo;
23 class GCNSubtarget;
24 
25 /// This is a minimal scheduler strategy.  The main difference between this
26 /// and the GenericScheduler is that GCNSchedStrategy uses different
27 /// heuristics to determine excess/critical pressure sets.  Its goal is to
28 /// maximize kernel occupancy (i.e. maximum number of waves per simd).
29 class GCNMaxOccupancySchedStrategy final : public GenericScheduler {
30   friend class GCNScheduleDAGMILive;
31 
32   SUnit *pickNodeBidirectional(bool &IsTopNode);
33 
34   void pickNodeFromQueue(SchedBoundary &Zone, const CandPolicy &ZonePolicy,
35                          const RegPressureTracker &RPTracker,
36                          SchedCandidate &Cand);
37 
38   void initCandidate(SchedCandidate &Cand, SUnit *SU,
39                      bool AtTop, const RegPressureTracker &RPTracker,
40                      const SIRegisterInfo *SRI,
41                      unsigned SGPRPressure, unsigned VGPRPressure);
42 
43   unsigned SGPRExcessLimit;
44   unsigned VGPRExcessLimit;
45   unsigned SGPRCriticalLimit;
46   unsigned VGPRCriticalLimit;
47 
48   unsigned TargetOccupancy;
49 
50   MachineFunction *MF;
51 
52 public:
53   GCNMaxOccupancySchedStrategy(const MachineSchedContext *C);
54 
55   SUnit *pickNode(bool &IsTopNode) override;
56 
57   void initialize(ScheduleDAGMI *DAG) override;
58 
setTargetOccupancy(unsigned Occ)59   void setTargetOccupancy(unsigned Occ) { TargetOccupancy = Occ; }
60 };
61 
62 class GCNScheduleDAGMILive final : public ScheduleDAGMILive {
63 
64   const GCNSubtarget &ST;
65 
66   SIMachineFunctionInfo &MFI;
67 
68   // Occupancy target at the beginning of function scheduling cycle.
69   unsigned StartingOccupancy;
70 
71   // Minimal real occupancy recorder for the function.
72   unsigned MinOccupancy;
73 
74   // Scheduling stage number.
75   unsigned Stage;
76 
77   // Current region index.
78   size_t RegionIdx;
79 
80   // Vector of regions recorder for later rescheduling
81   SmallVector<std::pair<MachineBasicBlock::iterator,
82                         MachineBasicBlock::iterator>, 32> Regions;
83 
84   // Region live-in cache.
85   SmallVector<GCNRPTracker::LiveRegSet, 32> LiveIns;
86 
87   // Region pressure cache.
88   SmallVector<GCNRegPressure, 32> Pressure;
89 
90   // Temporary basic block live-in cache.
91   DenseMap<const MachineBasicBlock*, GCNRPTracker::LiveRegSet> MBBLiveIns;
92 
93   DenseMap<MachineInstr *, GCNRPTracker::LiveRegSet> BBLiveInMap;
94   DenseMap<MachineInstr *, GCNRPTracker::LiveRegSet> getBBLiveInMap() const;
95 
96   // Return current region pressure.
97   GCNRegPressure getRealRegPressure() const;
98 
99   // Compute and cache live-ins and pressure for all regions in block.
100   void computeBlockPressure(const MachineBasicBlock *MBB);
101 
102 
103 public:
104   GCNScheduleDAGMILive(MachineSchedContext *C,
105                        std::unique_ptr<MachineSchedStrategy> S);
106 
107   void schedule() override;
108 
109   void finalizeSchedule() override;
110 };
111 
112 } // End namespace llvm
113 
114 #endif // GCNSCHEDSTRATEGY_H
115