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authorDimitry Andric <dim@FreeBSD.org>2019-08-21 18:13:02 +0000
committerDimitry Andric <dim@FreeBSD.org>2019-08-21 18:13:02 +0000
commit54db30ce18663e6c2991958f3b5d18362e8e93c4 (patch)
tree4aa6442802570767398cc83ba484e97b1309bdc2 /contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
parent35284c22e9c8348159b7ce032ea45f2cdeb65298 (diff)
parente6d1592492a3a379186bfb02bd0f4eda0669c0d5 (diff)
Merge llvm trunk r366426, resolve conflicts, and update FREEBSD-Xlist.
Notes
Notes: svn path=/projects/clang900-import/; revision=351344
Diffstat (limited to 'contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp')
-rw-r--r--contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp804
1 files changed, 760 insertions, 44 deletions
diff --git a/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 69ddbfb53958..885239e2faed 100644
--- a/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/contrib/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -1,9 +1,8 @@
//===-- 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.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
@@ -21,6 +20,7 @@
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/MC/MCInstrDesc.h"
@@ -38,6 +38,7 @@ using namespace llvm;
//===----------------------------------------------------------------------===//
GCNHazardRecognizer::GCNHazardRecognizer(const MachineFunction &MF) :
+ IsHazardRecognizerMode(false),
CurrCycleInstr(nullptr),
MF(MF),
ST(MF.getSubtarget<GCNSubtarget>()),
@@ -45,7 +46,8 @@ GCNHazardRecognizer::GCNHazardRecognizer(const MachineFunction &MF) :
TRI(TII.getRegisterInfo()),
ClauseUses(TRI.getNumRegUnits()),
ClauseDefs(TRI.getNumRegUnits()) {
- MaxLookAhead = 5;
+ MaxLookAhead = MF.getRegInfo().isPhysRegUsed(AMDGPU::AGPR0) ? 18 : 5;
+ TSchedModel.init(&ST);
}
void GCNHazardRecognizer::EmitInstruction(SUnit *SU) {
@@ -114,6 +116,12 @@ static bool isSendMsgTraceDataOrGDS(const SIInstrInfo &TII,
}
}
+static bool isPermlane(const MachineInstr &MI) {
+ unsigned Opcode = MI.getOpcode();
+ return Opcode == AMDGPU::V_PERMLANE16_B32 ||
+ Opcode == AMDGPU::V_PERMLANEX16_B32;
+}
+
static unsigned getHWReg(const SIInstrInfo *TII, const MachineInstr &RegInstr) {
const MachineOperand *RegOp = TII->getNamedOperand(RegInstr,
AMDGPU::OpName::simm16);
@@ -123,6 +131,8 @@ static unsigned getHWReg(const SIInstrInfo *TII, const MachineInstr &RegInstr) {
ScheduleHazardRecognizer::HazardType
GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
MachineInstr *MI = SU->getInstr();
+ if (MI->isBundle())
+ return NoHazard;
if (SIInstrInfo::isSMRD(*MI) && checkSMRDHazards(MI) > 0)
return NoopHazard;
@@ -133,6 +143,15 @@ GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
&& checkVMEMHazards(MI) > 0)
return NoopHazard;
+ if (ST.hasNSAtoVMEMBug() && checkNSAtoVMEMHazard(MI) > 0)
+ return NoopHazard;
+
+ if (checkFPAtomicToDenormModeHazard(MI) > 0)
+ return NoopHazard;
+
+ if (ST.hasNoDataDepHazard())
+ return NoHazard;
+
if (SIInstrInfo::isVALU(*MI) && checkVALUHazards(MI) > 0)
return NoopHazard;
@@ -163,6 +182,12 @@ GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
checkReadM0Hazards(MI) > 0)
return NoopHazard;
+ if (SIInstrInfo::isMAI(*MI) && checkMAIHazards(MI) > 0)
+ return NoopHazard;
+
+ if ((MI->mayLoad() || MI->mayStore()) && checkMAILdStHazards(MI) > 0)
+ return NoopHazard;
+
if (MI->isInlineAsm() && checkInlineAsmHazards(MI) > 0)
return NoopHazard;
@@ -172,22 +197,74 @@ GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
return NoHazard;
}
+static void insertNoopInBundle(MachineInstr *MI, const SIInstrInfo &TII) {
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(), TII.get(AMDGPU::S_NOP))
+ .addImm(0);
+}
+
+void GCNHazardRecognizer::processBundle() {
+ MachineBasicBlock::instr_iterator MI = std::next(CurrCycleInstr->getIterator());
+ MachineBasicBlock::instr_iterator E = CurrCycleInstr->getParent()->instr_end();
+ // Check bundled MachineInstr's for hazards.
+ for (; MI != E && MI->isInsideBundle(); ++MI) {
+ CurrCycleInstr = &*MI;
+ unsigned WaitStates = PreEmitNoopsCommon(CurrCycleInstr);
+
+ if (IsHazardRecognizerMode)
+ fixHazards(CurrCycleInstr);
+
+ for (unsigned i = 0; i < WaitStates; ++i)
+ insertNoopInBundle(CurrCycleInstr, TII);
+
+ // It’s unnecessary to track more than MaxLookAhead instructions. Since we
+ // include the bundled MI directly after, only add a maximum of
+ // (MaxLookAhead - 1) noops to EmittedInstrs.
+ for (unsigned i = 0, e = std::min(WaitStates, MaxLookAhead - 1); i < e; ++i)
+ EmittedInstrs.push_front(nullptr);
+
+ EmittedInstrs.push_front(CurrCycleInstr);
+ EmittedInstrs.resize(MaxLookAhead);
+ }
+ CurrCycleInstr = nullptr;
+}
+
unsigned GCNHazardRecognizer::PreEmitNoops(SUnit *SU) {
- return PreEmitNoops(SU->getInstr());
+ IsHazardRecognizerMode = false;
+ return PreEmitNoopsCommon(SU->getInstr());
}
unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
+ IsHazardRecognizerMode = true;
+ CurrCycleInstr = MI;
+ unsigned W = PreEmitNoopsCommon(MI);
+ fixHazards(MI);
+ CurrCycleInstr = nullptr;
+ return W;
+}
+
+unsigned GCNHazardRecognizer::PreEmitNoopsCommon(MachineInstr *MI) {
+ if (MI->isBundle())
+ return 0;
+
int WaitStates = std::max(0, checkAnyInstHazards(MI));
if (SIInstrInfo::isSMRD(*MI))
return std::max(WaitStates, checkSMRDHazards(MI));
- if (SIInstrInfo::isVALU(*MI))
- WaitStates = std::max(WaitStates, checkVALUHazards(MI));
-
if (SIInstrInfo::isVMEM(*MI) || SIInstrInfo::isFLAT(*MI))
WaitStates = std::max(WaitStates, checkVMEMHazards(MI));
+ if (ST.hasNSAtoVMEMBug())
+ WaitStates = std::max(WaitStates, checkNSAtoVMEMHazard(MI));
+
+ WaitStates = std::max(WaitStates, checkFPAtomicToDenormModeHazard(MI));
+
+ if (ST.hasNoDataDepHazard())
+ return WaitStates;
+
+ if (SIInstrInfo::isVALU(*MI))
+ WaitStates = std::max(WaitStates, checkVALUHazards(MI));
+
if (SIInstrInfo::isDPP(*MI))
WaitStates = std::max(WaitStates, checkDPPHazards(MI));
@@ -216,6 +293,12 @@ unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
if (ST.hasReadM0SendMsgHazard() && isSendMsgTraceDataOrGDS(TII, *MI))
return std::max(WaitStates, checkReadM0Hazards(MI));
+ if (SIInstrInfo::isMAI(*MI))
+ return std::max(WaitStates, checkMAIHazards(MI));
+
+ if (MI->mayLoad() || MI->mayStore())
+ return std::max(WaitStates, checkMAILdStHazards(MI));
+
return WaitStates;
}
@@ -232,10 +315,14 @@ void GCNHazardRecognizer::AdvanceCycle() {
// Do not track non-instructions which do not affect the wait states.
// If included, these instructions can lead to buffer overflow such that
// detectable hazards are missed.
- if (CurrCycleInstr->getOpcode() == AMDGPU::IMPLICIT_DEF)
+ if (CurrCycleInstr->isImplicitDef() || CurrCycleInstr->isDebugInstr() ||
+ CurrCycleInstr->isKill())
return;
- else if (CurrCycleInstr->isDebugInstr())
+
+ if (CurrCycleInstr->isBundle()) {
+ processBundle();
return;
+ }
unsigned NumWaitStates = TII.getNumWaitStates(*CurrCycleInstr);
@@ -266,41 +353,112 @@ void GCNHazardRecognizer::RecedeCycle() {
// Helper Functions
//===----------------------------------------------------------------------===//
-int GCNHazardRecognizer::getWaitStatesSince(
- function_ref<bool(MachineInstr *)> IsHazard) {
+typedef function_ref<bool(MachineInstr *, int WaitStates)> IsExpiredFn;
+
+// Returns a minimum wait states since \p I walking all predecessors.
+// Only scans until \p IsExpired does not return true.
+// Can only be run in a hazard recognizer mode.
+static int getWaitStatesSince(GCNHazardRecognizer::IsHazardFn IsHazard,
+ MachineBasicBlock *MBB,
+ MachineBasicBlock::reverse_instr_iterator I,
+ int WaitStates,
+ IsExpiredFn IsExpired,
+ DenseSet<const MachineBasicBlock *> &Visited) {
+ for (auto E = MBB->instr_rend(); I != E; ++I) {
+ // Don't add WaitStates for parent BUNDLE instructions.
+ if (I->isBundle())
+ continue;
+
+ if (IsHazard(&*I))
+ return WaitStates;
+
+ if (I->isInlineAsm() || I->isImplicitDef() || I->isDebugInstr())
+ continue;
+
+ WaitStates += SIInstrInfo::getNumWaitStates(*I);
+
+ if (IsExpired(&*I, WaitStates))
+ return std::numeric_limits<int>::max();
+ }
+
+ int MinWaitStates = WaitStates;
+ bool Found = false;
+ for (MachineBasicBlock *Pred : MBB->predecessors()) {
+ if (!Visited.insert(Pred).second)
+ continue;
+
+ int W = getWaitStatesSince(IsHazard, Pred, Pred->instr_rbegin(),
+ WaitStates, IsExpired, Visited);
+
+ if (W == std::numeric_limits<int>::max())
+ continue;
+
+ MinWaitStates = Found ? std::min(MinWaitStates, W) : W;
+ if (IsExpired(nullptr, MinWaitStates))
+ return MinWaitStates;
+
+ Found = true;
+ }
+
+ if (Found)
+ return MinWaitStates;
+
+ return std::numeric_limits<int>::max();
+}
+
+static int getWaitStatesSince(GCNHazardRecognizer::IsHazardFn IsHazard,
+ MachineInstr *MI,
+ IsExpiredFn IsExpired) {
+ DenseSet<const MachineBasicBlock *> Visited;
+ return getWaitStatesSince(IsHazard, MI->getParent(),
+ std::next(MI->getReverseIterator()),
+ 0, IsExpired, Visited);
+}
+
+int GCNHazardRecognizer::getWaitStatesSince(IsHazardFn IsHazard, int Limit) {
+ if (IsHazardRecognizerMode) {
+ auto IsExpiredFn = [Limit] (MachineInstr *, int WaitStates) {
+ return WaitStates >= Limit;
+ };
+ return ::getWaitStatesSince(IsHazard, CurrCycleInstr, IsExpiredFn);
+ }
+
int WaitStates = 0;
for (MachineInstr *MI : EmittedInstrs) {
if (MI) {
if (IsHazard(MI))
return WaitStates;
- unsigned Opcode = MI->getOpcode();
- if (Opcode == AMDGPU::INLINEASM)
+ if (MI->isInlineAsm())
continue;
}
++WaitStates;
+
+ if (WaitStates >= Limit)
+ break;
}
return std::numeric_limits<int>::max();
}
-int GCNHazardRecognizer::getWaitStatesSinceDef(
- unsigned Reg, function_ref<bool(MachineInstr *)> IsHazardDef) {
+int GCNHazardRecognizer::getWaitStatesSinceDef(unsigned Reg,
+ IsHazardFn IsHazardDef,
+ int Limit) {
const SIRegisterInfo *TRI = ST.getRegisterInfo();
auto IsHazardFn = [IsHazardDef, TRI, Reg] (MachineInstr *MI) {
return IsHazardDef(MI) && MI->modifiesRegister(Reg, TRI);
};
- return getWaitStatesSince(IsHazardFn);
+ return getWaitStatesSince(IsHazardFn, Limit);
}
-int GCNHazardRecognizer::getWaitStatesSinceSetReg(
- function_ref<bool(MachineInstr *)> IsHazard) {
+int GCNHazardRecognizer::getWaitStatesSinceSetReg(IsHazardFn IsHazard,
+ int Limit) {
auto IsHazardFn = [IsHazard] (MachineInstr *MI) {
return isSSetReg(MI->getOpcode()) && IsHazard(MI);
};
- return getWaitStatesSince(IsHazardFn);
+ return getWaitStatesSince(IsHazardFn, Limit);
}
//===----------------------------------------------------------------------===//
@@ -342,9 +500,9 @@ int GCNHazardRecognizer::checkSoftClauseHazards(MachineInstr *MEM) {
// 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
+ // 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 by another instruction in the clause
// (including itself). If we encounter this situaion, we need to break the
// clause by inserting a non SMEM instruction.
@@ -377,13 +535,12 @@ int GCNHazardRecognizer::checkSoftClauseHazards(MachineInstr *MEM) {
}
int GCNHazardRecognizer::checkSMRDHazards(MachineInstr *SMRD) {
- const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
int WaitStatesNeeded = 0;
WaitStatesNeeded = checkSoftClauseHazards(SMRD);
// This SMRD hazard only affects SI.
- if (ST.getGeneration() != AMDGPUSubtarget::SOUTHERN_ISLANDS)
+ if (!ST.hasSMRDReadVALUDefHazard())
return WaitStatesNeeded;
// A read of an SGPR by SMRD instruction requires 4 wait states when the
@@ -398,7 +555,8 @@ int GCNHazardRecognizer::checkSMRDHazards(MachineInstr *SMRD) {
if (!Use.isReg())
continue;
int WaitStatesNeededForUse =
- SmrdSgprWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardDefFn);
+ SmrdSgprWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardDefFn,
+ SmrdSgprWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
// This fixes what appears to be undocumented hardware behavior in SI where
@@ -411,7 +569,8 @@ int GCNHazardRecognizer::checkSMRDHazards(MachineInstr *SMRD) {
if (IsBufferSMRD) {
int WaitStatesNeededForUse =
SmrdSgprWaitStates - getWaitStatesSinceDef(Use.getReg(),
- IsBufferHazardDefFn);
+ IsBufferHazardDefFn,
+ SmrdSgprWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
}
}
@@ -420,7 +579,7 @@ int GCNHazardRecognizer::checkSMRDHazards(MachineInstr *SMRD) {
}
int GCNHazardRecognizer::checkVMEMHazards(MachineInstr* VMEM) {
- if (ST.getGeneration() < AMDGPUSubtarget::VOLCANIC_ISLANDS)
+ if (!ST.hasVMEMReadSGPRVALUDefHazard())
return 0;
int WaitStatesNeeded = checkSoftClauseHazards(VMEM);
@@ -429,13 +588,13 @@ int GCNHazardRecognizer::checkVMEMHazards(MachineInstr* VMEM) {
// SGPR was written by a VALU Instruction.
const int VmemSgprWaitStates = 5;
auto IsHazardDefFn = [this] (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);
+ VmemSgprWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardDefFn,
+ VmemSgprWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
}
return WaitStatesNeeded;
@@ -455,13 +614,16 @@ int GCNHazardRecognizer::checkDPPHazards(MachineInstr *DPP) {
if (!Use.isReg() || !TRI->isVGPR(MF.getRegInfo(), Use.getReg()))
continue;
int WaitStatesNeededForUse =
- DppVgprWaitStates - getWaitStatesSinceDef(Use.getReg());
+ DppVgprWaitStates - getWaitStatesSinceDef(Use.getReg(),
+ [](MachineInstr *) { return true; },
+ DppVgprWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
}
WaitStatesNeeded = std::max(
WaitStatesNeeded,
- DppExecWaitStates - getWaitStatesSinceDef(AMDGPU::EXEC, IsHazardDefFn));
+ DppExecWaitStates - getWaitStatesSinceDef(AMDGPU::EXEC, IsHazardDefFn,
+ DppExecWaitStates));
return WaitStatesNeeded;
}
@@ -473,7 +635,8 @@ int GCNHazardRecognizer::checkDivFMasHazards(MachineInstr *DivFMas) {
// instruction.
const int DivFMasWaitStates = 4;
auto IsHazardDefFn = [TII] (MachineInstr *MI) { return TII->isVALU(*MI); };
- int WaitStatesNeeded = getWaitStatesSinceDef(AMDGPU::VCC, IsHazardDefFn);
+ int WaitStatesNeeded = getWaitStatesSinceDef(AMDGPU::VCC, IsHazardDefFn,
+ DivFMasWaitStates);
return DivFMasWaitStates - WaitStatesNeeded;
}
@@ -486,7 +649,7 @@ int GCNHazardRecognizer::checkGetRegHazards(MachineInstr *GetRegInstr) {
auto IsHazardFn = [TII, GetRegHWReg] (MachineInstr *MI) {
return GetRegHWReg == getHWReg(TII, *MI);
};
- int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+ int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn, GetRegWaitStates);
return GetRegWaitStates - WaitStatesNeeded;
}
@@ -495,12 +658,11 @@ 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;
+ const int SetRegWaitStates = ST.getSetRegWaitStates();
auto IsHazardFn = [TII, HWReg] (MachineInstr *MI) {
return HWReg == getHWReg(TII, *MI);
};
- int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+ int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn, SetRegWaitStates);
return SetRegWaitStates - WaitStatesNeeded;
}
@@ -571,7 +733,7 @@ int GCNHazardRecognizer::checkVALUHazardsHelper(const MachineOperand &Def,
TRI->regsOverlap(MI->getOperand(DataIdx).getReg(), Reg);
};
int WaitStatesNeededForDef =
- VALUWaitStates - getWaitStatesSince(IsHazardFn);
+ VALUWaitStates - getWaitStatesSince(IsHazardFn, VALUWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForDef);
return WaitStatesNeeded;
@@ -636,12 +798,13 @@ int GCNHazardRecognizer::checkRWLaneHazards(MachineInstr *RWLane) {
};
const int RWLaneWaitStates = 4;
- int WaitStatesSince = getWaitStatesSinceDef(LaneSelectReg, IsHazardFn);
+ int WaitStatesSince = getWaitStatesSinceDef(LaneSelectReg, IsHazardFn,
+ RWLaneWaitStates);
return RWLaneWaitStates - WaitStatesSince;
}
int GCNHazardRecognizer::checkRFEHazards(MachineInstr *RFE) {
- if (ST.getGeneration() < AMDGPUSubtarget::VOLCANIC_ISLANDS)
+ if (!ST.hasRFEHazards())
return 0;
const SIInstrInfo *TII = ST.getInstrInfo();
@@ -651,7 +814,7 @@ int GCNHazardRecognizer::checkRFEHazards(MachineInstr *RFE) {
auto IsHazardFn = [TII] (MachineInstr *MI) {
return getHWReg(TII, *MI) == AMDGPU::Hwreg::ID_TRAPSTS;
};
- int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+ int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn, RFEWaitStates);
return RFEWaitStates - WaitStatesNeeded;
}
@@ -675,7 +838,8 @@ int GCNHazardRecognizer::checkAnyInstHazards(MachineInstr *MI) {
return MI->getOpcode() == AMDGPU::S_MOV_FED_B32;
};
int WaitStatesNeededForUse =
- MovFedWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardFn);
+ MovFedWaitStates - getWaitStatesSinceDef(Use.getReg(), IsHazardFn,
+ MovFedWaitStates);
WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
}
@@ -688,5 +852,557 @@ int GCNHazardRecognizer::checkReadM0Hazards(MachineInstr *MI) {
auto IsHazardFn = [TII] (MachineInstr *MI) {
return TII->isSALU(*MI);
};
- return SMovRelWaitStates - getWaitStatesSinceDef(AMDGPU::M0, IsHazardFn);
+ return SMovRelWaitStates - getWaitStatesSinceDef(AMDGPU::M0, IsHazardFn,
+ SMovRelWaitStates);
+}
+
+void GCNHazardRecognizer::fixHazards(MachineInstr *MI) {
+ fixVMEMtoScalarWriteHazards(MI);
+ fixVcmpxPermlaneHazards(MI);
+ fixSMEMtoVectorWriteHazards(MI);
+ fixVcmpxExecWARHazard(MI);
+ fixLdsBranchVmemWARHazard(MI);
+}
+
+bool GCNHazardRecognizer::fixVcmpxPermlaneHazards(MachineInstr *MI) {
+ if (!ST.hasVcmpxPermlaneHazard() || !isPermlane(*MI))
+ return false;
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ auto IsHazardFn = [TII] (MachineInstr *MI) {
+ return TII->isVOPC(*MI);
+ };
+
+ auto IsExpiredFn = [] (MachineInstr *MI, int) {
+ if (!MI)
+ return false;
+ unsigned Opc = MI->getOpcode();
+ return SIInstrInfo::isVALU(*MI) &&
+ Opc != AMDGPU::V_NOP_e32 &&
+ Opc != AMDGPU::V_NOP_e64 &&
+ Opc != AMDGPU::V_NOP_sdwa;
+ };
+
+ if (::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn) ==
+ std::numeric_limits<int>::max())
+ return false;
+
+ // V_NOP will be discarded by SQ.
+ // Use V_MOB_B32 v?, v?. Register must be alive so use src0 of V_PERMLANE*
+ // which is always a VGPR and available.
+ auto *Src0 = TII->getNamedOperand(*MI, AMDGPU::OpName::src0);
+ unsigned Reg = Src0->getReg();
+ bool IsUndef = Src0->isUndef();
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
+ TII->get(AMDGPU::V_MOV_B32_e32))
+ .addReg(Reg, RegState::Define | (IsUndef ? RegState::Dead : 0))
+ .addReg(Reg, IsUndef ? RegState::Undef : RegState::Kill);
+
+ return true;
+}
+
+bool GCNHazardRecognizer::fixVMEMtoScalarWriteHazards(MachineInstr *MI) {
+ if (!ST.hasVMEMtoScalarWriteHazard())
+ return false;
+
+ if (!SIInstrInfo::isSALU(*MI) && !SIInstrInfo::isSMRD(*MI))
+ return false;
+
+ if (MI->getNumDefs() == 0)
+ return false;
+
+ const SIRegisterInfo *TRI = ST.getRegisterInfo();
+
+ auto IsHazardFn = [TRI, MI] (MachineInstr *I) {
+ if (!SIInstrInfo::isVMEM(*I) && !SIInstrInfo::isDS(*I) &&
+ !SIInstrInfo::isFLAT(*I))
+ return false;
+
+ for (const MachineOperand &Def : MI->defs()) {
+ MachineOperand *Op = I->findRegisterUseOperand(Def.getReg(), false, TRI);
+ if (!Op)
+ continue;
+ return true;
+ }
+ return false;
+ };
+
+ auto IsExpiredFn = [] (MachineInstr *MI, int) {
+ return MI && (SIInstrInfo::isVALU(*MI) ||
+ (MI->getOpcode() == AMDGPU::S_WAITCNT &&
+ !MI->getOperand(0).getImm()));
+ };
+
+ if (::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn) ==
+ std::numeric_limits<int>::max())
+ return false;
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(), TII->get(AMDGPU::V_NOP_e32));
+ return true;
+}
+
+bool GCNHazardRecognizer::fixSMEMtoVectorWriteHazards(MachineInstr *MI) {
+ if (!ST.hasSMEMtoVectorWriteHazard())
+ return false;
+
+ if (!SIInstrInfo::isVALU(*MI))
+ return false;
+
+ unsigned SDSTName;
+ switch (MI->getOpcode()) {
+ case AMDGPU::V_READLANE_B32:
+ case AMDGPU::V_READFIRSTLANE_B32:
+ SDSTName = AMDGPU::OpName::vdst;
+ break;
+ default:
+ SDSTName = AMDGPU::OpName::sdst;
+ break;
+ }
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ const SIRegisterInfo *TRI = ST.getRegisterInfo();
+ const AMDGPU::IsaVersion IV = AMDGPU::getIsaVersion(ST.getCPU());
+ const MachineOperand *SDST = TII->getNamedOperand(*MI, SDSTName);
+ if (!SDST) {
+ for (const auto &MO : MI->implicit_operands()) {
+ if (MO.isDef() && TRI->isSGPRClass(TRI->getPhysRegClass(MO.getReg()))) {
+ SDST = &MO;
+ break;
+ }
+ }
+ }
+
+ if (!SDST)
+ return false;
+
+ const unsigned SDSTReg = SDST->getReg();
+ auto IsHazardFn = [SDSTReg, TRI] (MachineInstr *I) {
+ return SIInstrInfo::isSMRD(*I) && I->readsRegister(SDSTReg, TRI);
+ };
+
+ auto IsExpiredFn = [TII, IV] (MachineInstr *MI, int) {
+ if (MI) {
+ if (TII->isSALU(*MI)) {
+ switch (MI->getOpcode()) {
+ case AMDGPU::S_SETVSKIP:
+ case AMDGPU::S_VERSION:
+ case AMDGPU::S_WAITCNT_VSCNT:
+ case AMDGPU::S_WAITCNT_VMCNT:
+ case AMDGPU::S_WAITCNT_EXPCNT:
+ // These instructions cannot not mitigate the hazard.
+ return false;
+ case AMDGPU::S_WAITCNT_LGKMCNT:
+ // Reducing lgkmcnt count to 0 always mitigates the hazard.
+ return (MI->getOperand(1).getImm() == 0) &&
+ (MI->getOperand(0).getReg() == AMDGPU::SGPR_NULL);
+ case AMDGPU::S_WAITCNT: {
+ const int64_t Imm = MI->getOperand(0).getImm();
+ AMDGPU::Waitcnt Decoded = AMDGPU::decodeWaitcnt(IV, Imm);
+ return (Decoded.LgkmCnt == 0);
+ }
+ default:
+ // SOPP instructions cannot mitigate the hazard.
+ if (TII->isSOPP(*MI))
+ return false;
+ // At this point the SALU can be assumed to mitigate the hazard
+ // because either:
+ // (a) it is independent of the at risk SMEM (breaking chain),
+ // or
+ // (b) it is dependent on the SMEM, in which case an appropriate
+ // s_waitcnt lgkmcnt _must_ exist between it and the at risk
+ // SMEM instruction.
+ return true;
+ }
+ }
+ }
+ return false;
+ };
+
+ if (::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn) ==
+ std::numeric_limits<int>::max())
+ return false;
+
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
+ TII->get(AMDGPU::S_MOV_B32), AMDGPU::SGPR_NULL)
+ .addImm(0);
+ return true;
+}
+
+bool GCNHazardRecognizer::fixVcmpxExecWARHazard(MachineInstr *MI) {
+ if (!ST.hasVcmpxExecWARHazard() || !SIInstrInfo::isVALU(*MI))
+ return false;
+
+ const SIRegisterInfo *TRI = ST.getRegisterInfo();
+ if (!MI->modifiesRegister(AMDGPU::EXEC, TRI))
+ return false;
+
+ auto IsHazardFn = [TRI] (MachineInstr *I) {
+ if (SIInstrInfo::isVALU(*I))
+ return false;
+ return I->readsRegister(AMDGPU::EXEC, TRI);
+ };
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ auto IsExpiredFn = [TII, TRI] (MachineInstr *MI, int) {
+ if (!MI)
+ return false;
+ if (SIInstrInfo::isVALU(*MI)) {
+ if (TII->getNamedOperand(*MI, AMDGPU::OpName::sdst))
+ return true;
+ for (auto MO : MI->implicit_operands())
+ if (MO.isDef() && TRI->isSGPRClass(TRI->getPhysRegClass(MO.getReg())))
+ return true;
+ }
+ if (MI->getOpcode() == AMDGPU::S_WAITCNT_DEPCTR &&
+ (MI->getOperand(0).getImm() & 0xfffe) == 0xfffe)
+ return true;
+ return false;
+ };
+
+ if (::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn) ==
+ std::numeric_limits<int>::max())
+ return false;
+
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
+ TII->get(AMDGPU::S_WAITCNT_DEPCTR))
+ .addImm(0xfffe);
+ return true;
+}
+
+bool GCNHazardRecognizer::fixLdsBranchVmemWARHazard(MachineInstr *MI) {
+ if (!ST.hasLdsBranchVmemWARHazard())
+ return false;
+
+ auto IsHazardInst = [] (const MachineInstr *MI) {
+ if (SIInstrInfo::isDS(*MI))
+ return 1;
+ if (SIInstrInfo::isVMEM(*MI) || SIInstrInfo::isSegmentSpecificFLAT(*MI))
+ return 2;
+ return 0;
+ };
+
+ auto InstType = IsHazardInst(MI);
+ if (!InstType)
+ return false;
+
+ auto IsExpiredFn = [&IsHazardInst] (MachineInstr *I, int) {
+ return I && (IsHazardInst(I) ||
+ (I->getOpcode() == AMDGPU::S_WAITCNT_VSCNT &&
+ I->getOperand(0).getReg() == AMDGPU::SGPR_NULL &&
+ !I->getOperand(1).getImm()));
+ };
+
+ auto IsHazardFn = [InstType, &IsHazardInst] (MachineInstr *I) {
+ if (!I->isBranch())
+ return false;
+
+ auto IsHazardFn = [InstType, IsHazardInst] (MachineInstr *I) {
+ auto InstType2 = IsHazardInst(I);
+ return InstType2 && InstType != InstType2;
+ };
+
+ auto IsExpiredFn = [InstType, &IsHazardInst] (MachineInstr *I, int) {
+ if (!I)
+ return false;
+
+ auto InstType2 = IsHazardInst(I);
+ if (InstType == InstType2)
+ return true;
+
+ return I->getOpcode() == AMDGPU::S_WAITCNT_VSCNT &&
+ I->getOperand(0).getReg() == AMDGPU::SGPR_NULL &&
+ !I->getOperand(1).getImm();
+ };
+
+ return ::getWaitStatesSince(IsHazardFn, I, IsExpiredFn) !=
+ std::numeric_limits<int>::max();
+ };
+
+ if (::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn) ==
+ std::numeric_limits<int>::max())
+ return false;
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
+ TII->get(AMDGPU::S_WAITCNT_VSCNT))
+ .addReg(AMDGPU::SGPR_NULL, RegState::Undef)
+ .addImm(0);
+
+ return true;
+}
+
+int GCNHazardRecognizer::checkNSAtoVMEMHazard(MachineInstr *MI) {
+ int NSAtoVMEMWaitStates = 1;
+
+ if (!ST.hasNSAtoVMEMBug())
+ return 0;
+
+ if (!SIInstrInfo::isMUBUF(*MI) && !SIInstrInfo::isMTBUF(*MI))
+ return 0;
+
+ const SIInstrInfo *TII = ST.getInstrInfo();
+ const auto *Offset = TII->getNamedOperand(*MI, AMDGPU::OpName::offset);
+ if (!Offset || (Offset->getImm() & 6) == 0)
+ return 0;
+
+ auto IsHazardFn = [TII] (MachineInstr *I) {
+ if (!SIInstrInfo::isMIMG(*I))
+ return false;
+ const AMDGPU::MIMGInfo *Info = AMDGPU::getMIMGInfo(I->getOpcode());
+ return Info->MIMGEncoding == AMDGPU::MIMGEncGfx10NSA &&
+ TII->getInstSizeInBytes(*I) >= 16;
+ };
+
+ return NSAtoVMEMWaitStates - getWaitStatesSince(IsHazardFn, 1);
+}
+
+int GCNHazardRecognizer::checkFPAtomicToDenormModeHazard(MachineInstr *MI) {
+ int FPAtomicToDenormModeWaitStates = 3;
+
+ if (MI->getOpcode() != AMDGPU::S_DENORM_MODE)
+ return 0;
+
+ auto IsHazardFn = [] (MachineInstr *I) {
+ if (!SIInstrInfo::isVMEM(*I) && !SIInstrInfo::isFLAT(*I))
+ return false;
+ return SIInstrInfo::isFPAtomic(*I);
+ };
+
+ auto IsExpiredFn = [] (MachineInstr *MI, int WaitStates) {
+ if (WaitStates >= 3 || SIInstrInfo::isVALU(*MI))
+ return true;
+
+ switch (MI->getOpcode()) {
+ case AMDGPU::S_WAITCNT:
+ case AMDGPU::S_WAITCNT_VSCNT:
+ case AMDGPU::S_WAITCNT_VMCNT:
+ case AMDGPU::S_WAITCNT_EXPCNT:
+ case AMDGPU::S_WAITCNT_LGKMCNT:
+ case AMDGPU::S_WAITCNT_IDLE:
+ return true;
+ default:
+ break;
+ }
+
+ return false;
+ };
+
+
+ return FPAtomicToDenormModeWaitStates -
+ ::getWaitStatesSince(IsHazardFn, MI, IsExpiredFn);
+}
+
+int GCNHazardRecognizer::checkMAIHazards(MachineInstr *MI) {
+ assert(SIInstrInfo::isMAI(*MI));
+
+ int WaitStatesNeeded = 0;
+ unsigned Opc = MI->getOpcode();
+
+ auto IsVALUFn = [] (MachineInstr *MI) {
+ return SIInstrInfo::isVALU(*MI);
+ };
+
+ if (Opc != AMDGPU::V_ACCVGPR_READ_B32) { // MFMA or v_accvgpr_write
+ const int LegacyVALUWritesVGPRWaitStates = 2;
+ const int VALUWritesExecWaitStates = 4;
+ const int MaxWaitStates = 4;
+
+ int WaitStatesNeededForUse = VALUWritesExecWaitStates -
+ getWaitStatesSinceDef(AMDGPU::EXEC, IsVALUFn, MaxWaitStates);
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+
+ if (WaitStatesNeeded < MaxWaitStates) {
+ for (const MachineOperand &Use : MI->explicit_uses()) {
+ const int MaxWaitStates = 2;
+
+ if (!Use.isReg() || !TRI.isVGPR(MF.getRegInfo(), Use.getReg()))
+ continue;
+
+ int WaitStatesNeededForUse = LegacyVALUWritesVGPRWaitStates -
+ getWaitStatesSinceDef(Use.getReg(), IsVALUFn, MaxWaitStates);
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+
+ if (WaitStatesNeeded == MaxWaitStates)
+ break;
+ }
+ }
+ }
+
+ auto IsMFMAFn = [] (MachineInstr *MI) {
+ return SIInstrInfo::isMAI(*MI) &&
+ MI->getOpcode() != AMDGPU::V_ACCVGPR_WRITE_B32 &&
+ MI->getOpcode() != AMDGPU::V_ACCVGPR_READ_B32;
+ };
+
+ for (const MachineOperand &Op : MI->explicit_operands()) {
+ if (!Op.isReg() || !TRI.isAGPR(MF.getRegInfo(), Op.getReg()))
+ continue;
+
+ if (Op.isDef() && Opc != AMDGPU::V_ACCVGPR_WRITE_B32)
+ continue;
+
+ const int MFMAWritesAGPROverlappedSrcABWaitStates = 4;
+ const int MFMAWritesAGPROverlappedSrcCWaitStates = 2;
+ const int MFMA4x4WritesAGPRAccVgprReadWaitStates = 4;
+ const int MFMA16x16WritesAGPRAccVgprReadWaitStates = 10;
+ const int MFMA32x32WritesAGPRAccVgprReadWaitStates = 18;
+ const int MFMA4x4WritesAGPRAccVgprWriteWaitStates = 1;
+ const int MFMA16x16WritesAGPRAccVgprWriteWaitStates = 7;
+ const int MFMA32x32WritesAGPRAccVgprWriteWaitStates = 15;
+ const int MaxWaitStates = 18;
+ unsigned Reg = Op.getReg();
+ unsigned HazardDefLatency = 0;
+
+ auto IsOverlappedMFMAFn = [Reg, &IsMFMAFn, &HazardDefLatency, this]
+ (MachineInstr *MI) {
+ if (!IsMFMAFn(MI))
+ return false;
+ unsigned DstReg = MI->getOperand(0).getReg();
+ if (DstReg == Reg)
+ return false;
+ HazardDefLatency = std::max(HazardDefLatency,
+ TSchedModel.computeInstrLatency(MI));
+ return TRI.regsOverlap(DstReg, Reg);
+ };
+
+ int WaitStatesSinceDef = getWaitStatesSinceDef(Reg, IsOverlappedMFMAFn,
+ MaxWaitStates);
+ int NeedWaitStates = MFMAWritesAGPROverlappedSrcABWaitStates;
+ int SrcCIdx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::src2);
+ int OpNo = MI->getOperandNo(&Op);
+ if (OpNo == SrcCIdx) {
+ NeedWaitStates = MFMAWritesAGPROverlappedSrcCWaitStates;
+ } else if (Opc == AMDGPU::V_ACCVGPR_READ_B32) {
+ switch (HazardDefLatency) {
+ case 2: NeedWaitStates = MFMA4x4WritesAGPRAccVgprReadWaitStates;
+ break;
+ case 8: NeedWaitStates = MFMA16x16WritesAGPRAccVgprReadWaitStates;
+ break;
+ case 16: LLVM_FALLTHROUGH;
+ default: NeedWaitStates = MFMA32x32WritesAGPRAccVgprReadWaitStates;
+ break;
+ }
+ } else if (Opc == AMDGPU::V_ACCVGPR_WRITE_B32) {
+ switch (HazardDefLatency) {
+ case 2: NeedWaitStates = MFMA4x4WritesAGPRAccVgprWriteWaitStates;
+ break;
+ case 8: NeedWaitStates = MFMA16x16WritesAGPRAccVgprWriteWaitStates;
+ break;
+ case 16: LLVM_FALLTHROUGH;
+ default: NeedWaitStates = MFMA32x32WritesAGPRAccVgprWriteWaitStates;
+ break;
+ }
+ }
+
+ int WaitStatesNeededForUse = NeedWaitStates - WaitStatesSinceDef;
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+
+ if (WaitStatesNeeded == MaxWaitStates)
+ return WaitStatesNeeded; // Early exit.
+
+ auto IsAccVgprWriteFn = [Reg, this] (MachineInstr *MI) {
+ if (MI->getOpcode() != AMDGPU::V_ACCVGPR_WRITE_B32)
+ return false;
+ unsigned DstReg = MI->getOperand(0).getReg();
+ return TRI.regsOverlap(Reg, DstReg);
+ };
+
+ const int AccVGPRWriteMFMAReadSrcCWaitStates = 1;
+ const int AccVGPRWriteMFMAReadSrcABWaitStates = 3;
+ const int AccVGPRWriteAccVgprReadWaitStates = 3;
+ NeedWaitStates = AccVGPRWriteMFMAReadSrcABWaitStates;
+ if (OpNo == SrcCIdx)
+ NeedWaitStates = AccVGPRWriteMFMAReadSrcCWaitStates;
+ else if (Opc == AMDGPU::V_ACCVGPR_READ_B32)
+ NeedWaitStates = AccVGPRWriteAccVgprReadWaitStates;
+
+ WaitStatesNeededForUse = NeedWaitStates -
+ getWaitStatesSinceDef(Reg, IsAccVgprWriteFn, MaxWaitStates);
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+
+ if (WaitStatesNeeded == MaxWaitStates)
+ return WaitStatesNeeded; // Early exit.
+ }
+
+ if (Opc == AMDGPU::V_ACCVGPR_WRITE_B32) {
+ const int MFMA4x4ReadSrcCAccVgprWriteWaitStates = 0;
+ const int MFMA16x16ReadSrcCAccVgprWriteWaitStates = 5;
+ const int MFMA32x32ReadSrcCAccVgprWriteWaitStates = 13;
+ const int MaxWaitStates = 13;
+ unsigned DstReg = MI->getOperand(0).getReg();
+ unsigned HazardDefLatency = 0;
+
+ auto IsSrcCMFMAFn = [DstReg, &IsMFMAFn, &HazardDefLatency, this]
+ (MachineInstr *MI) {
+ if (!IsMFMAFn(MI))
+ return false;
+ unsigned Reg = TII.getNamedOperand(*MI, AMDGPU::OpName::src2)->getReg();
+ HazardDefLatency = std::max(HazardDefLatency,
+ TSchedModel.computeInstrLatency(MI));
+ return TRI.regsOverlap(Reg, DstReg);
+ };
+
+ int WaitStatesSince = getWaitStatesSince(IsSrcCMFMAFn, MaxWaitStates);
+ int NeedWaitStates;
+ switch (HazardDefLatency) {
+ case 2: NeedWaitStates = MFMA4x4ReadSrcCAccVgprWriteWaitStates;
+ break;
+ case 8: NeedWaitStates = MFMA16x16ReadSrcCAccVgprWriteWaitStates;
+ break;
+ case 16: LLVM_FALLTHROUGH;
+ default: NeedWaitStates = MFMA32x32ReadSrcCAccVgprWriteWaitStates;
+ break;
+ }
+
+ int WaitStatesNeededForUse = NeedWaitStates - WaitStatesSince;
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+ }
+
+ return WaitStatesNeeded;
+}
+
+int GCNHazardRecognizer::checkMAILdStHazards(MachineInstr *MI) {
+ if (!ST.hasMAIInsts())
+ return 0;
+
+ int WaitStatesNeeded = 0;
+
+ auto IsAccVgprReadFn = [] (MachineInstr *MI) {
+ return MI->getOpcode() == AMDGPU::V_ACCVGPR_READ_B32;
+ };
+
+ for (const MachineOperand &Op : MI->explicit_uses()) {
+ if (!Op.isReg() || !TRI.isVGPR(MF.getRegInfo(), Op.getReg()))
+ continue;
+
+ unsigned Reg = Op.getReg();
+
+ const int AccVgprReadLdStWaitStates = 2;
+ const int VALUWriteAccVgprReadLdStDepVALUWaitStates = 1;
+ const int MaxWaitStates = 2;
+
+ int WaitStatesNeededForUse = AccVgprReadLdStWaitStates -
+ getWaitStatesSinceDef(Reg, IsAccVgprReadFn, MaxWaitStates);
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+
+ if (WaitStatesNeeded == MaxWaitStates)
+ return WaitStatesNeeded; // Early exit.
+
+ auto IsVALUAccVgprReadCheckFn = [Reg, this] (MachineInstr *MI) {
+ if (MI->getOpcode() != AMDGPU::V_ACCVGPR_READ_B32)
+ return false;
+ auto IsVALUFn = [] (MachineInstr *MI) {
+ return SIInstrInfo::isVALU(*MI) && !SIInstrInfo::isMAI(*MI);
+ };
+ return getWaitStatesSinceDef(Reg, IsVALUFn, 2 /*MaxWaitStates*/) <
+ std::numeric_limits<int>::max();
+ };
+
+ WaitStatesNeededForUse = VALUWriteAccVgprReadLdStDepVALUWaitStates -
+ getWaitStatesSince(IsVALUAccVgprReadCheckFn, MaxWaitStates);
+ WaitStatesNeeded = std::max(WaitStatesNeeded, WaitStatesNeededForUse);
+ }
+
+ return WaitStatesNeeded;
}