lib/Target/PowerPC/PPCHazardRecognizers.h

   1 //===-- PPCHazardRecognizers.h - PowerPC Hazard Recognizers -----*- 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 // This file defines hazard recognizers for scheduling on PowerPC processors.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_LIB_TARGET_POWERPC_PPCHAZARDRECOGNIZERS_H
  14 #define LLVM_LIB_TARGET_POWERPC_PPCHAZARDRECOGNIZERS_H
  15
  16 #include "PPCInstrInfo.h"
  17 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
  18 #include "llvm/CodeGen/ScoreboardHazardRecognizer.h"
  19 #include "llvm/CodeGen/SelectionDAGNodes.h"
  20
  21 namespace llvm {
  22
  23 /// PPCDispatchGroupSBHazardRecognizer - This class implements a scoreboard-based
  24 /// hazard recognizer for PPC ooo processors with dispatch-group hazards.
  25 class PPCDispatchGroupSBHazardRecognizer : public ScoreboardHazardRecognizer {
  26   const ScheduleDAG *DAG;
  27   SmallVector<SUnit *, 7> CurGroup;
  28   unsigned CurSlots, CurBranches;
  29
  30   bool isLoadAfterStore(SUnit *SU);
  31   bool isBCTRAfterSet(SUnit *SU);
  32   bool mustComeFirst(const MCInstrDesc *MCID, unsigned &NSlots);
  33 public:
  34   PPCDispatchGroupSBHazardRecognizer(const InstrItineraryData *ItinData,
  35                          const ScheduleDAG *DAG_) :
  36     ScoreboardHazardRecognizer(ItinData, DAG_), DAG(DAG_),
  37     CurSlots(0), CurBranches(0) {}
  38
  39   HazardType getHazardType(SUnit *SU, int Stalls) override;
  40   bool ShouldPreferAnother(SUnit* SU) override;
  41   unsigned PreEmitNoops(SUnit *SU) override;
  42   void EmitInstruction(SUnit *SU) override;
  43   void AdvanceCycle() override;
  44   void RecedeCycle() override;
  45   void Reset() override;
  46   void EmitNoop() override;
  47 };
  48
  49 /// PPCHazardRecognizer970 - This class defines a finite state automata that
  50 /// models the dispatch logic on the PowerPC 970 (aka G5) processor.  This
  51 /// promotes good dispatch group formation and implements noop insertion to
  52 /// avoid structural hazards that cause significant performance penalties (e.g.
  53 /// setting the CTR register then branching through it within a dispatch group),
  54 /// or storing then loading from the same address within a dispatch group.
  55 class PPCHazardRecognizer970 : public ScheduleHazardRecognizer {
  56   const ScheduleDAG &DAG;
  57
  58   unsigned NumIssued;  // Number of insts issued, including advanced cycles.
  59
  60   // Various things that can cause a structural hazard.
  61
  62   // HasCTRSet - If the CTR register is set in this group, disallow BCTRL.
  63   bool HasCTRSet;
  64
  65   // StoredPtr - Keep track of the address of any store.  If we see a load from
  66   // the same address (or one that aliases it), disallow the store.  We can have
  67   // up to four stores in one dispatch group, hence we track up to 4.
  68   //
  69   // This is null if we haven't seen a store yet.  We keep track of both
  70   // operands of the store here, since we support [r+r] and [r+i] addressing.
  71   const Value *StoreValue[4];
  72   int64_t StoreOffset[4];
  73   uint64_t StoreSize[4];
  74   unsigned NumStores;
  75
  76 public:
  77   PPCHazardRecognizer970(const ScheduleDAG &DAG);
  78   HazardType getHazardType(SUnit *SU, int Stalls) override;
  79   void EmitInstruction(SUnit *SU) override;
  80   void AdvanceCycle() override;
  81   void Reset() override;
  82
  83 private:
  84   /// EndDispatchGroup - Called when we are finishing a new dispatch group.
  85   ///
  86   void EndDispatchGroup();
  87
  88   /// GetInstrType - Classify the specified powerpc opcode according to its
  89   /// pipeline.
  90   PPCII::PPC970_Unit GetInstrType(unsigned Opcode,
  91                                   bool &isFirst, bool &isSingle,bool &isCracked,
  92                                   bool &isLoad, bool &isStore);
  93
  94   bool isLoadOfStoredAddress(uint64_t LoadSize, int64_t LoadOffset,
  95                              const Value *LoadValue) const;
  96 };
  97
  98 } // end namespace llvm
  99
 100 #endif
 101