1 files changed, 502 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
new file mode 100644
index 000000000000..dd3b46f13921
--- /dev/null
+++ b/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -0,0 +1,502 @@
+//===-- GCNHazardRecognizers.cpp - GCN Hazard Recognizer Impls ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements hazard recognizers for scheduling on GCN processors.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GCNHazardRecognizer.h"
+#include "AMDGPUSubtarget.h"
+#include "SIInstrInfo.h"
+#include "llvm/CodeGen/ScheduleDAG.h"
+#include "llvm/Support/Debug.h"
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// Hazard Recoginizer Implementation
+//===----------------------------------------------------------------------===//
+
+GCNHazardRecognizer::GCNHazardRecognizer(const MachineFunction &MF) :
+  CurrCycleInstr(nullptr),
+  MF(MF),
+  ST(MF.getSubtarget<SISubtarget>()) {
+  MaxLookAhead = 5;
+}
+
+void GCNHazardRecognizer::EmitInstruction(SUnit *SU) {
+  EmitInstruction(SU->getInstr());
+}
+
+void GCNHazardRecognizer::EmitInstruction(MachineInstr *MI) {
+  CurrCycleInstr = MI;
+}
+
+static bool isDivFMas(unsigned Opcode) {
+  return Opcode == AMDGPU::V_DIV_FMAS_F32 || Opcode == AMDGPU::V_DIV_FMAS_F64;
+}
+
+static bool isSGetReg(unsigned Opcode) {
+  return Opcode == AMDGPU::S_GETREG_B32;
+}
+
+static bool isSSetReg(unsigned Opcode) {
+  return Opcode == AMDGPU::S_SETREG_B32 || Opcode == AMDGPU::S_SETREG_IMM32_B32;
+}
+
+static bool isRWLane(unsigned Opcode) {
+  return Opcode == AMDGPU::V_READLANE_B32 || Opcode == AMDGPU::V_WRITELANE_B32;
+}
+
+static bool isRFE(unsigned Opcode) {
+  return Opcode == AMDGPU::S_RFE_B64;
+}
+
+static unsigned getHWReg(const SIInstrInfo *TII, const MachineInstr &RegInstr) {
+
+  const MachineOperand *RegOp = TII->getNamedOperand(RegInstr,
+                                                     AMDGPU::OpName::simm16);
+  return RegOp->getImm() & AMDGPU::Hwreg::ID_MASK_;
+}
+
+ScheduleHazardRecognizer::HazardType
+GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
+  MachineInstr *MI = SU->getInstr();
+
+  if (SIInstrInfo::isSMRD(*MI) && checkSMRDHazards(MI) > 0)
+    return NoopHazard;
+
+  if (SIInstrInfo::isVMEM(*MI) && checkVMEMHazards(MI) > 0)
+    return NoopHazard;
+
+  if (SIInstrInfo::isVALU(*MI) && checkVALUHazards(MI) > 0)
+    return NoopHazard;
+
+  if (SIInstrInfo::isDPP(*MI) && checkDPPHazards(MI) > 0)
+    return NoopHazard;
+
+  if (isDivFMas(MI->getOpcode()) && checkDivFMasHazards(MI) > 0)
+    return NoopHazard;
+
+  if (isRWLane(MI->getOpcode()) && checkRWLaneHazards(MI) > 0)
+    return NoopHazard;
+
+  if (isSGetReg(MI->getOpcode()) && checkGetRegHazards(MI) > 0)
+    return NoopHazard;
+
+  if (isSSetReg(MI->getOpcode()) && checkSetRegHazards(MI) > 0)
+    return NoopHazard;
+
+  if (isRFE(MI->getOpcode()) && checkRFEHazards(MI) > 0)
+    return NoopHazard;
+
+  return NoHazard;
+}
+
+unsigned GCNHazardRecognizer::PreEmitNoops(SUnit *SU) {
+  return PreEmitNoops(SU->getInstr());
+}
+
+unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
+  if (SIInstrInfo::isSMRD(*MI))
+    return std::max(0, checkSMRDHazards(MI));
+
+  if (SIInstrInfo::isVALU(*MI)) {
+    int WaitStates = std::max(0, checkVALUHazards(MI));
+
+    if (SIInstrInfo::isVMEM(*MI))
+      WaitStates = std::max(WaitStates, checkVMEMHazards(MI));
+
+    if (SIInstrInfo::isDPP(*MI))
+      WaitStates = std::max(WaitStates, checkDPPHazards(MI));
+
+    if (isDivFMas(MI->getOpcode()))
+      WaitStates = std::max(WaitStates, checkDivFMasHazards(MI));
+
+    if (isRWLane(MI->getOpcode()))
+      WaitStates = std::max(WaitStates, checkRWLaneHazards(MI));
+
+    return WaitStates;
+  }
+
+  if (isSGetReg(MI->getOpcode()))
+    return std::max(0, checkGetRegHazards(MI));
+
+  if (isSSetReg(MI->getOpcode()))
+    return std::max(0, checkSetRegHazards(MI));
+
+  if (isRFE(MI->getOpcode()))
+    return std::max(0, checkRFEHazards(MI));
+
+  return 0;
+}
+
+void GCNHazardRecognizer::EmitNoop() {
+  EmittedInstrs.push_front(nullptr);
+}
+
+void GCNHazardRecognizer::AdvanceCycle() {
+
+  // When the scheduler detects a stall, it will call AdvanceCycle() without
+  // emitting any instructions.
+  if (!CurrCycleInstr)
+    return;
+
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  unsigned NumWaitStates = TII->getNumWaitStates(*CurrCycleInstr);
+
+  // Keep track of emitted instructions
+  EmittedInstrs.push_front(CurrCycleInstr);
+
+  // Add a nullptr for each additional wait state after the first.  Make sure
+  // not to add more than getMaxLookAhead() items to the list, since we
+  // truncate the list to that size right after this loop.
+  for (unsigned i = 1, e = std::min(NumWaitStates, getMaxLookAhead());
+       i < e; ++i) {
+    EmittedInstrs.push_front(nullptr);
+  }
+
+  // getMaxLookahead() is the largest number of wait states we will ever need
+  // to insert, so there is no point in keeping track of more than that many
+  // wait states.
+  EmittedInstrs.resize(getMaxLookAhead());
+
+  CurrCycleInstr = nullptr;
+}
+
+void GCNHazardRecognizer::RecedeCycle() {
+  llvm_unreachable("hazard recognizer does not support bottom-up scheduling.");
+}
+
+//===----------------------------------------------------------------------===//
+// Helper Functions
+//===----------------------------------------------------------------------===//
+
+int GCNHazardRecognizer::getWaitStatesSince(
+    function_ref<bool(MachineInstr *)> IsHazard) {
+
+  int WaitStates = -1;
+  for (MachineInstr *MI : EmittedInstrs) {
+    ++WaitStates;
+    if (!MI || !IsHazard(MI))
+      continue;
+    return WaitStates;
+  }
+  return std::numeric_limits<int>::max();
+}
+
+int GCNHazardRecognizer::getWaitStatesSinceDef(
+    unsigned Reg, function_ref<bool(MachineInstr *)> IsHazardDef) {
+  const SIRegisterInfo *TRI = ST.getRegisterInfo();
+
+  auto IsHazardFn = [IsHazardDef, TRI, Reg] (MachineInstr *MI) {
+    return IsHazardDef(MI) && MI->modifiesRegister(Reg, TRI);
+  };
+
+  return getWaitStatesSince(IsHazardFn);
+}
+
+int GCNHazardRecognizer::getWaitStatesSinceSetReg(
+    function_ref<bool(MachineInstr *)> IsHazard) {
+
+  auto IsHazardFn = [IsHazard] (MachineInstr *MI) {
+    return isSSetReg(MI->getOpcode()) && IsHazard(MI);
+  };
+
+  return getWaitStatesSince(IsHazardFn);
+}
+
+//===----------------------------------------------------------------------===//
+// No-op Hazard Detection
+//===----------------------------------------------------------------------===//
+
+static void addRegsToSet(iterator_range<MachineInstr::const_mop_iterator> Ops,
+                         std::set<unsigned> &Set) {
+  for (const MachineOperand &Op : Ops) {
+    if (Op.isReg())
+      Set.insert(Op.getReg());
+  }
+}
+
+int GCNHazardRecognizer::checkSMEMSoftClauseHazards(MachineInstr *SMEM) {
+  // SMEM soft clause are only present on VI+
+  if (ST.getGeneration() < SISubtarget::VOLCANIC_ISLANDS)
+    return 0;
+
+  // A soft-clause is any group of consecutive SMEM instructions.  The
+  // instructions in this group may return out of order and/or may be
+  // replayed (i.e. the same instruction issued more than once).
+  //
+  // In order to handle these situations correctly we need to make sure
+  // that when a clause has more than one instruction, no instruction in the
+  // clause writes to a register that is read another instruction in the clause
+  // (including itself). If we encounter this situaion, we need to break the
+  // clause by inserting a non SMEM instruction.
+
+  std::set<unsigned> ClauseDefs;
+  std::set<unsigned> ClauseUses;
+
+  for (MachineInstr *MI : EmittedInstrs) {
+
+    // When we hit a non-SMEM instruction then we have passed the start of the
+    // clause and we can stop.
+    if (!MI || !SIInstrInfo::isSMRD(*MI))
+      break;
+
+    addRegsToSet(MI->defs(), ClauseDefs);
+    addRegsToSet(MI->uses(), ClauseUses);
+  }
+
+  if (ClauseDefs.empty())
+    return 0;
+
+  // FIXME: When we support stores, we need to make sure not to put loads and
+  // stores in the same clause if they use the same address.  For now, just
+  // start a new clause whenever we see a store.
+  if (SMEM->mayStore())
+    return 1;
+
+  addRegsToSet(SMEM->defs(), ClauseDefs);
+  addRegsToSet(SMEM->uses(), ClauseUses);
+
+  std::vector<unsigned> Result(std::max(ClauseDefs.size(), ClauseUses.size()));
+  std::vector<unsigned>::iterator End;
+
+  End = std::set_intersection(ClauseDefs.begin(), ClauseDefs.end(),
+                              ClauseUses.begin(), ClauseUses.end(), Result.begin());
+
+  // If the set of defs and uses intersect then we cannot add this instruction
+  // to the clause, so we have a hazard.
+  if (End != Result.begin())
+    return 1;
+
+  return 0;
+}
+
+int GCNHazardRecognizer::checkSMRDHazards(MachineInstr *SMRD) {
+  const SISubtarget &ST = MF.getSubtarget<SISubtarget>();
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  int WaitStatesNeeded = 0;
+
+  WaitStatesNeeded = checkSMEMSoftClauseHazards(SMRD);
+
+  // This SMRD hazard only affects SI.
+  if (ST.getGeneration() != SISubtarget::SOUTHERN_ISLANDS)
+    return WaitStatesNeeded;
+
+  // A read of an SGPR by SMRD instruction requires 4 wait states when the
+  // SGPR was written by a VALU instruction.
+  int SmrdSgprWaitStates = 4;
+  auto IsHazardDefFn = [TII] (MachineInstr *MI) { return TII->isVALU(*MI); };
+
+  for (const MachineOperand &Use : SMRD->uses()) {
+    if (!Use.isReg())
+      continue;
+    int WaitStatesNeededForUse =
+        SmrdSgprWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardDefFn);
+    WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+  }
+  return WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkVMEMHazards(MachineInstr* VMEM) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+
+  if (ST.getGeneration() < SISubtarget::VOLCANIC_ISLANDS)
+    return 0;
+
+  const SIRegisterInfo &TRI = TII->getRegisterInfo();
+
+  // A read of an SGPR by a VMEM instruction requires 5 wait states when the
+  // SGPR was written by a VALU Instruction.
+  int VmemSgprWaitStates = 5;
+  int WaitStatesNeeded = 0;
+  auto IsHazardDefFn = [TII] (MachineInstr *MI) { return TII->isVALU(*MI); };
+
+  for (const MachineOperand &Use : VMEM->uses()) {
+    if (!Use.isReg() || TRI.isVGPR(MF.getRegInfo(), Use.getReg()))
+      continue;
+
+    int WaitStatesNeededForUse =
+        VmemSgprWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardDefFn);
+    WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+  }
+  return WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkDPPHazards(MachineInstr *DPP) {
+  const SIRegisterInfo *TRI = ST.getRegisterInfo();
+
+  // Check for DPP VGPR read after VALU VGPR write.
+  int DppVgprWaitStates = 2;
+  int WaitStatesNeeded = 0;
+
+  for (const MachineOperand &Use : DPP->uses()) {
+    if (!Use.isReg() || !TRI->isVGPR(MF.getRegInfo(), Use.getReg()))
+      continue;
+    int WaitStatesNeededForUse =
+        DppVgprWaitStates - getWaitStatesSinceDef(Use.getReg());
+    WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+  }
+
+  return WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkDivFMasHazards(MachineInstr *DivFMas) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+
+  // v_div_fmas requires 4 wait states after a write to vcc from a VALU
+  // instruction.
+  const int DivFMasWaitStates = 4;
+  auto IsHazardDefFn = [TII] (MachineInstr *MI) { return TII->isVALU(*MI); };
+  int WaitStatesNeeded = getWaitStatesSinceDef(AMDGPU::VCC, IsHazardDefFn);
+
+  return DivFMasWaitStates - WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkGetRegHazards(MachineInstr *GetRegInstr) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  unsigned GetRegHWReg = getHWReg(TII, *GetRegInstr);
+
+  const int GetRegWaitStates = 2;
+  auto IsHazardFn = [TII, GetRegHWReg] (MachineInstr *MI) {
+    return GetRegHWReg == getHWReg(TII, *MI);
+  };
+  int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+
+  return GetRegWaitStates - WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkSetRegHazards(MachineInstr *SetRegInstr) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  unsigned HWReg = getHWReg(TII, *SetRegInstr);
+
+  const int SetRegWaitStates =
+      ST.getGeneration() <= AMDGPUSubtarget::SEA_ISLANDS ? 1 : 2;
+  auto IsHazardFn = [TII, HWReg] (MachineInstr *MI) {
+    return HWReg == getHWReg(TII, *MI);
+  };
+  int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+  return SetRegWaitStates - WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::createsVALUHazard(const MachineInstr &MI) {
+  if (!MI.mayStore())
+    return -1;
+
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  unsigned Opcode = MI.getOpcode();
+  const MCInstrDesc &Desc = MI.getDesc();
+
+  int VDataIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::vdata);
+  int VDataRCID = -1;
+  if (VDataIdx != -1)
+    VDataRCID = Desc.OpInfo[VDataIdx].RegClass;
+
+  if (TII->isMUBUF(MI) || TII->isMTBUF(MI)) {
+    // There is no hazard if the instruction does not use vector regs
+    // (like wbinvl1)
+    if (VDataIdx == -1)
+      return -1;
+    // For MUBUF/MTBUF instructions this hazard only exists if the
+    // instruction is not using a register in the soffset field.
+    const MachineOperand *SOffset =
+        TII->getNamedOperand(MI, AMDGPU::OpName::soffset);
+    // If we have no soffset operand, then assume this field has been
+    // hardcoded to zero.
+    if (AMDGPU::getRegBitWidth(VDataRCID) > 64 &&
+        (!SOffset || !SOffset->isReg()))
+      return VDataIdx;
+  }
+
+  // MIMG instructions create a hazard if they don't use a 256-bit T# and
+  // the store size is greater than 8 bytes and they have more than two bits
+  // of their dmask set.
+  // All our MIMG definitions use a 256-bit T#, so we can skip checking for them.
+  if (TII->isMIMG(MI)) {
+    int SRsrcIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::srsrc);
+    assert(SRsrcIdx != -1 &&
+           AMDGPU::getRegBitWidth(Desc.OpInfo[SRsrcIdx].RegClass) == 256);
+    (void)SRsrcIdx;
+  }
+
+  if (TII->isFLAT(MI)) {
+    int DataIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::vdata);
+    if (AMDGPU::getRegBitWidth(Desc.OpInfo[DataIdx].RegClass) > 64)
+      return DataIdx;
+  }
+
+  return -1;
+}
+
+int GCNHazardRecognizer::checkVALUHazards(MachineInstr *VALU) {
+  // This checks for the hazard where VMEM instructions that store more than
+  // 8 bytes can have there store data over written by the next instruction.
+  if (!ST.has12DWordStoreHazard())
+    return 0;
+
+  const SIRegisterInfo *TRI = ST.getRegisterInfo();
+  const MachineRegisterInfo &MRI = VALU->getParent()->getParent()->getRegInfo();
+
+  const int VALUWaitStates = 1;
+  int WaitStatesNeeded = 0;
+
+  for (const MachineOperand &Def : VALU->defs()) {
+    if (!TRI->isVGPR(MRI, Def.getReg()))
+      continue;
+    unsigned Reg = Def.getReg();
+    auto IsHazardFn = [this, Reg, TRI] (MachineInstr *MI) {
+      int DataIdx = createsVALUHazard(*MI);
+      return DataIdx >= 0 &&
+             TRI->regsOverlap(MI->getOperand(DataIdx).getReg(), Reg);
+    };
+    int WaitStatesNeededForDef =
+        VALUWaitStates - getWaitStatesSince(IsHazardFn);
+    WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForDef);
+  }
+  return WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkRWLaneHazards(MachineInstr *RWLane) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  const SIRegisterInfo *TRI = ST.getRegisterInfo();
+  const MachineRegisterInfo &MRI =
+      RWLane->getParent()->getParent()->getRegInfo();
+
+  const MachineOperand *LaneSelectOp =
+      TII->getNamedOperand(*RWLane, AMDGPU::OpName::src1);
+
+  if (!LaneSelectOp->isReg() || !TRI->isSGPRReg(MRI, LaneSelectOp->getReg()))
+    return 0;
+
+  unsigned LaneSelectReg = LaneSelectOp->getReg();
+  auto IsHazardFn = [TII] (MachineInstr *MI) {
+    return TII->isVALU(*MI);
+  };
+
+  const int RWLaneWaitStates = 4;
+  int WaitStatesSince = getWaitStatesSinceDef(LaneSelectReg, IsHazardFn);
+  return RWLaneWaitStates - WaitStatesSince;
+}
+
+int GCNHazardRecognizer::checkRFEHazards(MachineInstr *RFE) {
+
+  if (ST.getGeneration() < AMDGPUSubtarget::VOLCANIC_ISLANDS)
+    return 0;
+
+  const SIInstrInfo *TII = ST.getInstrInfo();
+
+  const int RFEWaitStates = 1;
+
+  auto IsHazardFn = [TII] (MachineInstr *MI) {
+    return getHWReg(TII, *MI) == AMDGPU::Hwreg::ID_TRAPSTS;
+  };
+  int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+  return RFEWaitStates - WaitStatesNeeded;
+}