LLVM  10.0.0svn
HexagonHazardRecognizer.h
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1 //===--- HexagonHazardRecognizer.h - Hexagon Post RA Hazard Recognizer ----===//
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 // This file defines the hazard recognizer for scheduling on Hexagon.
9 //===----------------------------------------------------------------------===//
10 
11 #ifndef LLVM_LIB_TARGET_HEXAGON_HEXAGONPROFITRECOGNIZER_H
12 #define LLVM_LIB_TARGET_HEXAGON_HEXAGONPROFITRECOGNIZER_H
13 
14 #include "HexagonInstrInfo.h"
15 #include "HexagonSubtarget.h"
16 #include "llvm/ADT/SmallSet.h"
19 
20 namespace llvm {
21 
23  DFAPacketizer *Resources;
24  const HexagonInstrInfo *TII;
25  unsigned PacketNum = 0;
26  // If the packet contains a potential dot cur instruction. This is
27  // used for the scheduling priority function.
28  SUnit *UsesDotCur = nullptr;
29  // The packet number when a dor cur is emitted. If its use is not generated
30  // in the same packet, then try to wait another cycle before emitting.
31  int DotCurPNum = -1;
32  // Does the packet contain a load. Used to restrict another load, if possible.
33  bool UsesLoad = false;
34  // Check if we should prefer a vector store that will become a .new version.
35  // The .new store uses different resources than a normal store, and the
36  // packetizer will not generate the .new if the regular store does not have
37  // resources available (even if the .new version does). To help, the schedule
38  // attempts to schedule the .new as soon as possible in the packet.
39  SUnit *PrefVectorStoreNew = nullptr;
40  // The set of registers defined by instructions in the current packet.
41  SmallSet<unsigned, 8> RegDefs;
42 
43 public:
45  const HexagonInstrInfo *HII,
46  const HexagonSubtarget &ST)
47  : Resources(ST.createDFAPacketizer(II)), TII(HII) { }
48 
50  if (Resources)
51  delete Resources;
52  }
53 
54  /// This callback is invoked when a new block of instructions is about to be
55  /// scheduled. The hazard state is set to an initialized state.
56  void Reset() override;
57 
58  /// Return the hazard type of emitting this node. There are three
59  /// possible results. Either:
60  /// * NoHazard: it is legal to issue this instruction on this cycle.
61  /// * Hazard: issuing this instruction would stall the machine. If some
62  /// other instruction is available, issue it first.
63  HazardType getHazardType(SUnit *SU, int stalls) override;
64 
65  /// This callback is invoked when an instruction is emitted to be scheduled,
66  /// to advance the hazard state.
67  void EmitInstruction(SUnit *) override;
68 
69  /// This callback may be invoked if getHazardType returns NoHazard. If, even
70  /// though there is no hazard, it would be better to schedule another
71  /// available instruction, this callback should return true.
72  bool ShouldPreferAnother(SUnit *) override;
73 
74  /// This callback is invoked whenever the next top-down instruction to be
75  /// scheduled cannot issue in the current cycle, either because of latency
76  /// or resource conflicts. This should increment the internal state of the
77  /// hazard recognizer so that previously "Hazard" instructions will now not
78  /// be hazards.
79  void AdvanceCycle() override;
80 };
81 
82 } // end namespace llvm
83 
84 #endif // LLVM_LIB_TARGET_HEXAGON_HEXAGONPROFITRECOGNIZER_H
bool ShouldPreferAnother(SUnit *) override
This callback may be invoked if getHazardType returns NoHazard.
This class represents lattice values for constants.
Definition: AllocatorList.h:23
void EmitInstruction(SUnit *) override
This callback is invoked when an instruction is emitted to be scheduled, to advance the hazard state...
void AdvanceCycle() override
This callback is invoked whenever the next top-down instruction to be scheduled cannot issue in the c...
HazardType getHazardType(SUnit *SU, int stalls) override
Return the hazard type of emitting this node.
void Reset() override
This callback is invoked when a new block of instructions is about to be scheduled.
Itinerary data supplied by a subtarget to be used by a target.
HazardRecognizer - This determines whether or not an instruction can be issued this cycle...
HexagonHazardRecognizer(const InstrItineraryData *II, const HexagonInstrInfo *HII, const HexagonSubtarget &ST)
Scheduling unit. This is a node in the scheduling DAG.
Definition: ScheduleDAG.h:242