forked from OSchip/llvm-project
389 lines
12 KiB
C++
389 lines
12 KiB
C++
//===-- HexagonSubtarget.cpp - Hexagon Subtarget Information --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the Hexagon specific subclass of TargetSubtarget.
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//
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//===----------------------------------------------------------------------===//
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#include "HexagonSubtarget.h"
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#include "Hexagon.h"
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#include "HexagonRegisterInfo.h"
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#include "llvm/CodeGen/ScheduleDAG.h"
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#include "llvm/CodeGen/ScheduleDAGInstrs.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <map>
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using namespace llvm;
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#define DEBUG_TYPE "hexagon-subtarget"
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#define GET_SUBTARGETINFO_CTOR
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#define GET_SUBTARGETINFO_TARGET_DESC
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#include "HexagonGenSubtargetInfo.inc"
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static cl::opt<bool> EnableMemOps("enable-hexagon-memops",
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cl::Hidden, cl::ZeroOrMore, cl::ValueDisallowed, cl::init(true),
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cl::desc("Generate V4 MEMOP in code generation for Hexagon target"));
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static cl::opt<bool> DisableMemOps("disable-hexagon-memops",
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cl::Hidden, cl::ZeroOrMore, cl::ValueDisallowed, cl::init(false),
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cl::desc("Do not generate V4 MEMOP in code generation for Hexagon target"));
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static cl::opt<bool> EnableIEEERndNear("enable-hexagon-ieee-rnd-near",
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cl::Hidden, cl::ZeroOrMore, cl::init(false),
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cl::desc("Generate non-chopped conversion from fp to int."));
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static cl::opt<bool> EnableBSBSched("enable-bsb-sched",
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cl::Hidden, cl::ZeroOrMore, cl::init(true));
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static cl::opt<bool> EnableHexagonHVXDouble("enable-hexagon-hvx-double",
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cl::Hidden, cl::ZeroOrMore, cl::init(false),
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cl::desc("Enable Hexagon Double Vector eXtensions"));
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static cl::opt<bool> EnableHexagonHVX("enable-hexagon-hvx",
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cl::Hidden, cl::ZeroOrMore, cl::init(false),
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cl::desc("Enable Hexagon Vector eXtensions"));
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static cl::opt<bool> EnableTCLatencySched("enable-tc-latency-sched",
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cl::Hidden, cl::ZeroOrMore, cl::init(false));
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static cl::opt<bool> EnableDotCurSched("enable-cur-sched",
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cl::Hidden, cl::ZeroOrMore, cl::init(true),
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cl::desc("Enable the scheduler to generate .cur"));
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static cl::opt<bool> EnableVecFrwdSched("enable-evec-frwd-sched",
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cl::Hidden, cl::ZeroOrMore, cl::init(true));
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static cl::opt<bool> DisableHexagonMISched("disable-hexagon-misched",
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cl::Hidden, cl::ZeroOrMore, cl::init(false),
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cl::desc("Disable Hexagon MI Scheduling"));
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static cl::opt<bool> EnableSubregLiveness("hexagon-subreg-liveness",
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cl::Hidden, cl::ZeroOrMore, cl::init(true),
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cl::desc("Enable subregister liveness tracking for Hexagon"));
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static cl::opt<bool> OverrideLongCalls("hexagon-long-calls",
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cl::Hidden, cl::ZeroOrMore, cl::init(false),
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cl::desc("If present, forces/disables the use of long calls"));
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void HexagonSubtarget::initializeEnvironment() {
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UseMemOps = false;
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ModeIEEERndNear = false;
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UseBSBScheduling = false;
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}
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HexagonSubtarget &
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HexagonSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS) {
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CPUString = Hexagon_MC::selectHexagonCPU(getTargetTriple(), CPU);
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static std::map<StringRef, HexagonArchEnum> CpuTable {
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{ "hexagonv4", V4 },
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{ "hexagonv5", V5 },
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{ "hexagonv55", V55 },
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{ "hexagonv60", V60 },
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};
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auto foundIt = CpuTable.find(CPUString);
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if (foundIt != CpuTable.end())
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HexagonArchVersion = foundIt->second;
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else
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llvm_unreachable("Unrecognized Hexagon processor version");
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UseHVXOps = false;
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UseHVXDblOps = false;
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UseLongCalls = false;
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ParseSubtargetFeatures(CPUString, FS);
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if (EnableHexagonHVX.getPosition())
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UseHVXOps = EnableHexagonHVX;
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if (EnableHexagonHVXDouble.getPosition())
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UseHVXDblOps = EnableHexagonHVXDouble;
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if (OverrideLongCalls.getPosition())
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UseLongCalls = OverrideLongCalls;
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return *this;
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}
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HexagonSubtarget::HexagonSubtarget(const Triple &TT, StringRef CPU,
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StringRef FS, const TargetMachine &TM)
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: HexagonGenSubtargetInfo(TT, CPU, FS), CPUString(CPU),
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InstrInfo(initializeSubtargetDependencies(CPU, FS)), TLInfo(TM, *this),
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FrameLowering() {
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initializeEnvironment();
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// Initialize scheduling itinerary for the specified CPU.
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InstrItins = getInstrItineraryForCPU(CPUString);
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// UseMemOps on by default unless disabled explicitly
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if (DisableMemOps)
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UseMemOps = false;
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else if (EnableMemOps)
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UseMemOps = true;
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else
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UseMemOps = false;
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if (EnableIEEERndNear)
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ModeIEEERndNear = true;
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else
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ModeIEEERndNear = false;
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UseBSBScheduling = hasV60TOps() && EnableBSBSched;
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}
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void HexagonSubtarget::HexagonDAGMutation::apply(ScheduleDAGInstrs *DAG) {
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for (auto &SU : DAG->SUnits) {
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if (!SU.isInstr())
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continue;
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SmallVector<SDep, 4> Erase;
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for (auto &D : SU.Preds)
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if (D.getKind() == SDep::Output && D.getReg() == Hexagon::USR_OVF)
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Erase.push_back(D);
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for (auto &E : Erase)
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SU.removePred(E);
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}
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for (auto &SU : DAG->SUnits) {
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// Update the latency of chain edges between v60 vector load or store
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// instructions to be 1. These instructions cannot be scheduled in the
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// same packet.
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MachineInstr &MI1 = *SU.getInstr();
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auto *QII = static_cast<const HexagonInstrInfo*>(DAG->TII);
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bool IsStoreMI1 = MI1.mayStore();
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bool IsLoadMI1 = MI1.mayLoad();
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if (!QII->isV60VectorInstruction(MI1) || !(IsStoreMI1 || IsLoadMI1))
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continue;
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for (auto &SI : SU.Succs) {
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if (SI.getKind() != SDep::Order || SI.getLatency() != 0)
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continue;
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MachineInstr &MI2 = *SI.getSUnit()->getInstr();
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if (!QII->isV60VectorInstruction(MI2))
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continue;
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if ((IsStoreMI1 && MI2.mayStore()) || (IsLoadMI1 && MI2.mayLoad())) {
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SI.setLatency(1);
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SU.setHeightDirty();
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// Change the dependence in the opposite direction too.
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for (auto &PI : SI.getSUnit()->Preds) {
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if (PI.getSUnit() != &SU || PI.getKind() != SDep::Order)
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continue;
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PI.setLatency(1);
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SI.getSUnit()->setDepthDirty();
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}
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}
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}
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}
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}
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void HexagonSubtarget::getPostRAMutations(
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std::vector<std::unique_ptr<ScheduleDAGMutation>> &Mutations) const {
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Mutations.push_back(make_unique<HexagonSubtarget::HexagonDAGMutation>());
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}
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// Pin the vtable to this file.
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void HexagonSubtarget::anchor() {}
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bool HexagonSubtarget::enableMachineScheduler() const {
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if (DisableHexagonMISched.getNumOccurrences())
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return !DisableHexagonMISched;
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return true;
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}
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bool HexagonSubtarget::enableSubRegLiveness() const {
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return EnableSubregLiveness;
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}
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// This helper function is responsible for increasing the latency only.
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void HexagonSubtarget::updateLatency(MachineInstr &SrcInst,
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MachineInstr &DstInst, SDep &Dep) const {
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if (!hasV60TOps())
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return;
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auto &QII = static_cast<const HexagonInstrInfo&>(*getInstrInfo());
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if (EnableVecFrwdSched && QII.addLatencyToSchedule(SrcInst, DstInst)) {
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// Vec frwd scheduling.
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Dep.setLatency(Dep.getLatency() + 1);
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} else if (useBSBScheduling() &&
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QII.isLateInstrFeedsEarlyInstr(SrcInst, DstInst)) {
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// BSB scheduling.
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Dep.setLatency(Dep.getLatency() + 1);
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} else if (EnableTCLatencySched) {
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// TClass latency scheduling.
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// Check if SrcInst produces in 2C an operand of DstInst taken in stage 2B.
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if (QII.isTC1(SrcInst) || QII.isTC2(SrcInst))
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if (!QII.isTC1(DstInst) && !QII.isTC2(DstInst))
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Dep.setLatency(Dep.getLatency() + 1);
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}
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}
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/// If the SUnit has a zero latency edge, return the other SUnit.
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static SUnit *getZeroLatency(SUnit *N, SmallVector<SDep, 4> &Deps) {
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for (auto &I : Deps)
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if (I.isAssignedRegDep() && I.getLatency() == 0 &&
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!I.getSUnit()->getInstr()->isPseudo())
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return I.getSUnit();
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return nullptr;
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}
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/// Change the latency between the two SUnits.
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void HexagonSubtarget::changeLatency(SUnit *Src, SmallVector<SDep, 4> &Deps,
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SUnit *Dst, unsigned Lat) const {
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MachineInstr &SrcI = *Src->getInstr();
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for (auto &I : Deps) {
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if (I.getSUnit() != Dst)
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continue;
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I.setLatency(Lat);
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SUnit *UpdateDst = I.getSUnit();
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updateLatency(SrcI, *UpdateDst->getInstr(), I);
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// Update the latency of opposite edge too.
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for (auto &PI : UpdateDst->Preds) {
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if (PI.getSUnit() != Src || !PI.isAssignedRegDep())
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continue;
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PI.setLatency(Lat);
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updateLatency(SrcI, *UpdateDst->getInstr(), PI);
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}
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}
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}
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// Return true if these are the best two instructions to schedule
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// together with a zero latency. Only one dependence should have a zero
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// latency. If there are multiple choices, choose the best, and change
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// ther others, if needed.
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bool HexagonSubtarget::isBestZeroLatency(SUnit *Src, SUnit *Dst,
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const HexagonInstrInfo *TII) const {
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MachineInstr &SrcInst = *Src->getInstr();
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MachineInstr &DstInst = *Dst->getInstr();
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// Ignore Boundary SU nodes as these have null instructions.
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if (Dst->isBoundaryNode())
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return false;
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if (SrcInst.isPHI() || DstInst.isPHI())
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return false;
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// Check if the Dst instruction is the best candidate first.
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SUnit *Best = nullptr;
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SUnit *DstBest = nullptr;
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SUnit *SrcBest = getZeroLatency(Dst, Dst->Preds);
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if (SrcBest == nullptr || Src->NodeNum >= SrcBest->NodeNum) {
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// Check that Src doesn't have a better candidate.
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DstBest = getZeroLatency(Src, Src->Succs);
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if (DstBest == nullptr || Dst->NodeNum <= DstBest->NodeNum)
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Best = Dst;
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}
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if (Best != Dst)
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return false;
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// The caller frequents adds the same dependence twice. If so, then
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// return true for this case too.
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if (Src == SrcBest && Dst == DstBest)
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return true;
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// Reassign the latency for the previous bests, which requires setting
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// the dependence edge in both directions.
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if (SrcBest != nullptr)
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changeLatency(SrcBest, SrcBest->Succs, Dst, 1);
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if (DstBest != nullptr)
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changeLatency(Src, Src->Succs, DstBest, 1);
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// If there is an edge from SrcBest to DstBst, then try to change that
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// to 0 now.
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if (SrcBest && DstBest)
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changeLatency(SrcBest, SrcBest->Succs, DstBest, 0);
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return true;
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}
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// Update the latency of a Phi when the Phi bridges two instructions that
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// require a multi-cycle latency.
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void HexagonSubtarget::changePhiLatency(MachineInstr &SrcInst, SUnit *Dst,
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SDep &Dep) const {
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if (!SrcInst.isPHI() || Dst->NumPreds == 0 || Dep.getLatency() != 0)
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return;
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for (const SDep &PI : Dst->Preds) {
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if (PI.getLatency() != 0)
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continue;
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Dep.setLatency(2);
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break;
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}
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}
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/// \brief Perform target specific adjustments to the latency of a schedule
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/// dependency.
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void HexagonSubtarget::adjustSchedDependency(SUnit *Src, SUnit *Dst,
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SDep &Dep) const {
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MachineInstr *SrcInst = Src->getInstr();
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MachineInstr *DstInst = Dst->getInstr();
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if (!Src->isInstr() || !Dst->isInstr())
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return;
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const HexagonInstrInfo *QII = static_cast<const HexagonInstrInfo *>(getInstrInfo());
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// Instructions with .new operands have zero latency.
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if (QII->canExecuteInBundle(*SrcInst, *DstInst) &&
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isBestZeroLatency(Src, Dst, QII)) {
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Dep.setLatency(0);
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return;
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}
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if (!hasV60TOps())
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return;
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// Don't adjust the latency of post-increment part of the instruction.
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if (QII->isPostIncrement(*SrcInst) && Dep.isAssignedRegDep()) {
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if (SrcInst->mayStore())
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return;
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if (Dep.getReg() != SrcInst->getOperand(0).getReg())
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return;
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} else if (QII->isPostIncrement(*DstInst) && Dep.getKind() == SDep::Anti) {
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if (DstInst->mayStore())
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return;
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if (Dep.getReg() != DstInst->getOperand(0).getReg())
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return;
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} else if (QII->isPostIncrement(*DstInst) && DstInst->mayStore() &&
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Dep.isAssignedRegDep()) {
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MachineOperand &Op = DstInst->getOperand(DstInst->getNumOperands() - 1);
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if (Op.isReg() && Dep.getReg() != Op.getReg())
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return;
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}
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// Check if we need to change any the latency values when Phis are added.
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if (useBSBScheduling() && SrcInst->isPHI()) {
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changePhiLatency(*SrcInst, Dst, Dep);
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return;
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}
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// If it's a REG_SEQUENCE, use its destination instruction to determine
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// the correct latency.
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if (DstInst->isRegSequence() && Dst->NumSuccs == 1)
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DstInst = Dst->Succs[0].getSUnit()->getInstr();
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// Try to schedule uses near definitions to generate .cur.
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if (EnableDotCurSched && QII->isToBeScheduledASAP(*SrcInst, *DstInst) &&
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isBestZeroLatency(Src, Dst, QII)) {
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Dep.setLatency(0);
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return;
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}
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updateLatency(*SrcInst, *DstInst, Dep);
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}
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unsigned HexagonSubtarget::getL1CacheLineSize() const {
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return 32;
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}
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unsigned HexagonSubtarget::getL1PrefetchDistance() const {
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return 32;
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}
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