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llvm-mirror/lib/Target/Hexagon/HexagonOptAddrMode.cpp
Scott Constable 694f018415 Move RDF from Hexagon to Codegen 
RDF is designed to be target agnostic. Therefore it would be useful to have it available for other targets, such as X86.

Based on a previous patch by Krzysztof Parzyszek

Differential Revision: https://reviews.llvm.org/D75932
2020-03-17 12:43:14 -07:00

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//===- HexagonOptAddrMode.cpp ---------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// This implements a Hexagon-specific pass to optimize addressing mode for
// load/store instructions.
//===----------------------------------------------------------------------===//
#include "HexagonInstrInfo.h"
#include "HexagonSubtarget.h"
#include "MCTargetDesc/HexagonBaseInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineDominanceFrontier.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RDFGraph.h"
#include "llvm/CodeGen/RDFLiveness.h"
#include "llvm/CodeGen/RDFRegisters.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/InitializePasses.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
#define DEBUG_TYPE "opt-addr-mode"
using namespace llvm;
using namespace rdf;
static cl::opt<int> CodeGrowthLimit("hexagon-amode-growth-limit",
cl::Hidden, cl::init(0), cl::desc("Code growth limit for address mode "
"optimization"));
namespace llvm {
FunctionPass *createHexagonOptAddrMode();
void initializeHexagonOptAddrModePass(PassRegistry&);
} // end namespace llvm
namespace {
class HexagonOptAddrMode : public MachineFunctionPass {
public:
static char ID;
HexagonOptAddrMode() : MachineFunctionPass(ID) {}
StringRef getPassName() const override {
return "Optimize addressing mode of load/store";
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<MachineDominatorTree>();
AU.addRequired<MachineDominanceFrontier>();
AU.setPreservesAll();
}
bool runOnMachineFunction(MachineFunction &MF) override;
private:
using MISetType = DenseSet<MachineInstr *>;
using InstrEvalMap = DenseMap<MachineInstr *, bool>;
MachineRegisterInfo *MRI = nullptr;
const HexagonInstrInfo *HII = nullptr;
const HexagonRegisterInfo *HRI = nullptr;
MachineDominatorTree *MDT = nullptr;
DataFlowGraph *DFG = nullptr;
DataFlowGraph::DefStackMap DefM;
Liveness *LV = nullptr;
MISetType Deleted;
bool processBlock(NodeAddr<BlockNode *> BA);
bool xformUseMI(MachineInstr *TfrMI, MachineInstr *UseMI,
NodeAddr<UseNode *> UseN, unsigned UseMOnum);
bool processAddUses(NodeAddr<StmtNode *> AddSN, MachineInstr *AddMI,
const NodeList &UNodeList);
bool updateAddUses(MachineInstr *AddMI, MachineInstr *UseMI);
bool analyzeUses(unsigned DefR, const NodeList &UNodeList,
InstrEvalMap &InstrEvalResult, short &SizeInc);
bool hasRepForm(MachineInstr &MI, unsigned TfrDefR);
bool canRemoveAddasl(NodeAddr<StmtNode *> AddAslSN, MachineInstr &MI,
const NodeList &UNodeList);
bool isSafeToExtLR(NodeAddr<StmtNode *> SN, MachineInstr *MI,
unsigned LRExtReg, const NodeList &UNodeList);
void getAllRealUses(NodeAddr<StmtNode *> SN, NodeList &UNodeList);
bool allValidCandidates(NodeAddr<StmtNode *> SA, NodeList &UNodeList);
short getBaseWithLongOffset(const MachineInstr &MI) const;
bool changeStore(MachineInstr *OldMI, MachineOperand ImmOp,
unsigned ImmOpNum);
bool changeLoad(MachineInstr *OldMI, MachineOperand ImmOp, unsigned ImmOpNum);
bool changeAddAsl(NodeAddr<UseNode *> AddAslUN, MachineInstr *AddAslMI,
const MachineOperand &ImmOp, unsigned ImmOpNum);
bool isValidOffset(MachineInstr *MI, int Offset);
};
} // end anonymous namespace
char HexagonOptAddrMode::ID = 0;
INITIALIZE_PASS_BEGIN(HexagonOptAddrMode, "amode-opt",
"Optimize addressing mode", false, false)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_DEPENDENCY(MachineDominanceFrontier)
INITIALIZE_PASS_END(HexagonOptAddrMode, "amode-opt", "Optimize addressing mode",
false, false)
bool HexagonOptAddrMode::hasRepForm(MachineInstr &MI, unsigned TfrDefR) {
const MCInstrDesc &MID = MI.getDesc();
if ((!MID.mayStore() && !MID.mayLoad()) || HII->isPredicated(MI))
return false;
if (MID.mayStore()) {
MachineOperand StOp = MI.getOperand(MI.getNumOperands() - 1);
if (StOp.isReg() && StOp.getReg() == TfrDefR)
return false;
}
if (HII->getAddrMode(MI) == HexagonII::BaseRegOffset)
// Tranform to Absolute plus register offset.
return (HII->changeAddrMode_rr_ur(MI) >= 0);
else if (HII->getAddrMode(MI) == HexagonII::BaseImmOffset)
// Tranform to absolute addressing mode.
return (HII->changeAddrMode_io_abs(MI) >= 0);
return false;
}
// Check if addasl instruction can be removed. This is possible only
// if it's feeding to only load/store instructions with base + register
// offset as these instruction can be tranformed to use 'absolute plus
// shifted register offset'.
// ex:
// Rs = ##foo
// Rx = addasl(Rs, Rt, #2)
// Rd = memw(Rx + #28)
// Above three instructions can be replaced with Rd = memw(Rt<<#2 + ##foo+28)
bool HexagonOptAddrMode::canRemoveAddasl(NodeAddr<StmtNode *> AddAslSN,
MachineInstr &MI,
const NodeList &UNodeList) {
// check offset size in addasl. if 'offset > 3' return false
const MachineOperand &OffsetOp = MI.getOperand(3);
if (!OffsetOp.isImm() || OffsetOp.getImm() > 3)
return false;
Register OffsetReg = MI.getOperand(2).getReg();
RegisterRef OffsetRR;
NodeId OffsetRegRD = 0;
for (NodeAddr<UseNode *> UA : AddAslSN.Addr->members_if(DFG->IsUse, *DFG)) {
RegisterRef RR = UA.Addr->getRegRef(*DFG);
if (OffsetReg == RR.Reg) {
OffsetRR = RR;
OffsetRegRD = UA.Addr->getReachingDef();
}
}
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UA = *I;
NodeAddr<InstrNode *> IA = UA.Addr->getOwner(*DFG);
if (UA.Addr->getFlags() & NodeAttrs::PhiRef)
return false;
NodeAddr<RefNode*> AA = LV->getNearestAliasedRef(OffsetRR, IA);
if ((DFG->IsDef(AA) && AA.Id != OffsetRegRD) ||
AA.Addr->getReachingDef() != OffsetRegRD)
return false;
MachineInstr &UseMI = *NodeAddr<StmtNode *>(IA).Addr->getCode();
NodeAddr<DefNode *> OffsetRegDN = DFG->addr<DefNode *>(OffsetRegRD);
// Reaching Def to an offset register can't be a phi.
if ((OffsetRegDN.Addr->getFlags() & NodeAttrs::PhiRef) &&
MI.getParent() != UseMI.getParent())
return false;
const MCInstrDesc &UseMID = UseMI.getDesc();
if ((!UseMID.mayLoad() && !UseMID.mayStore()) ||
HII->getAddrMode(UseMI) != HexagonII::BaseImmOffset ||
getBaseWithLongOffset(UseMI) < 0)
return false;
// Addasl output can't be a store value.
if (UseMID.mayStore() && UseMI.getOperand(2).isReg() &&
UseMI.getOperand(2).getReg() == MI.getOperand(0).getReg())
return false;
for (auto &Mo : UseMI.operands())
if (Mo.isFI())
return false;
}
return true;
}
bool HexagonOptAddrMode::allValidCandidates(NodeAddr<StmtNode *> SA,
NodeList &UNodeList) {
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UN = *I;
RegisterRef UR = UN.Addr->getRegRef(*DFG);
NodeSet Visited, Defs;
const auto &P = LV->getAllReachingDefsRec(UR, UN, Visited, Defs);
if (!P.second) {
LLVM_DEBUG({
dbgs() << "*** Unable to collect all reaching defs for use ***\n"
<< PrintNode<UseNode*>(UN, *DFG) << '\n'
<< "The program's complexity may exceed the limits.\n";
});
return false;
}
const auto &ReachingDefs = P.first;
if (ReachingDefs.size() > 1) {
LLVM_DEBUG({
dbgs() << "*** Multiple Reaching Defs found!!! ***\n";
for (auto DI : ReachingDefs) {
NodeAddr<UseNode *> DA = DFG->addr<UseNode *>(DI);
NodeAddr<StmtNode *> TempIA = DA.Addr->getOwner(*DFG);
dbgs() << "\t\t[Reaching Def]: "
<< Print<NodeAddr<InstrNode *>>(TempIA, *DFG) << "\n";
}
});
return false;
}
}
return true;
}
void HexagonOptAddrMode::getAllRealUses(NodeAddr<StmtNode *> SA,
NodeList &UNodeList) {
for (NodeAddr<DefNode *> DA : SA.Addr->members_if(DFG->IsDef, *DFG)) {
LLVM_DEBUG(dbgs() << "\t\t[DefNode]: "
<< Print<NodeAddr<DefNode *>>(DA, *DFG) << "\n");
RegisterRef DR = DFG->getPRI().normalize(DA.Addr->getRegRef(*DFG));
auto UseSet = LV->getAllReachedUses(DR, DA);
for (auto UI : UseSet) {
NodeAddr<UseNode *> UA = DFG->addr<UseNode *>(UI);
LLVM_DEBUG({
NodeAddr<StmtNode *> TempIA = UA.Addr->getOwner(*DFG);
dbgs() << "\t\t\t[Reached Use]: "
<< Print<NodeAddr<InstrNode *>>(TempIA, *DFG) << "\n";
});
if (UA.Addr->getFlags() & NodeAttrs::PhiRef) {
NodeAddr<PhiNode *> PA = UA.Addr->getOwner(*DFG);
NodeId id = PA.Id;
const Liveness::RefMap &phiUse = LV->getRealUses(id);
LLVM_DEBUG(dbgs() << "\t\t\t\tphi real Uses"
<< Print<Liveness::RefMap>(phiUse, *DFG) << "\n");
if (!phiUse.empty()) {
for (auto I : phiUse) {
if (!DFG->getPRI().alias(RegisterRef(I.first), DR))
continue;
auto phiUseSet = I.second;
for (auto phiUI : phiUseSet) {
NodeAddr<UseNode *> phiUA = DFG->addr<UseNode *>(phiUI.first);
UNodeList.push_back(phiUA);
}
}
}
} else
UNodeList.push_back(UA);
}
}
}
bool HexagonOptAddrMode::isSafeToExtLR(NodeAddr<StmtNode *> SN,
MachineInstr *MI, unsigned LRExtReg,
const NodeList &UNodeList) {
RegisterRef LRExtRR;
NodeId LRExtRegRD = 0;
// Iterate through all the UseNodes in SN and find the reaching def
// for the LRExtReg.
for (NodeAddr<UseNode *> UA : SN.Addr->members_if(DFG->IsUse, *DFG)) {
RegisterRef RR = UA.Addr->getRegRef(*DFG);
if (LRExtReg == RR.Reg) {
LRExtRR = RR;
LRExtRegRD = UA.Addr->getReachingDef();
}
}
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UA = *I;
NodeAddr<InstrNode *> IA = UA.Addr->getOwner(*DFG);
// The reaching def of LRExtRR at load/store node should be same as the
// one reaching at the SN.
if (UA.Addr->getFlags() & NodeAttrs::PhiRef)
return false;
NodeAddr<RefNode*> AA = LV->getNearestAliasedRef(LRExtRR, IA);
if ((DFG->IsDef(AA) && AA.Id != LRExtRegRD) ||
AA.Addr->getReachingDef() != LRExtRegRD) {
LLVM_DEBUG(
dbgs() << "isSafeToExtLR: Returning false; another reaching def\n");
return false;
}
MachineInstr *UseMI = NodeAddr<StmtNode *>(IA).Addr->getCode();
NodeAddr<DefNode *> LRExtRegDN = DFG->addr<DefNode *>(LRExtRegRD);
// Reaching Def to LRExtReg can't be a phi.
if ((LRExtRegDN.Addr->getFlags() & NodeAttrs::PhiRef) &&
MI->getParent() != UseMI->getParent())
return false;
}
return true;
}
bool HexagonOptAddrMode::isValidOffset(MachineInstr *MI, int Offset) {
unsigned AlignMask = 0;
switch (HII->getMemAccessSize(*MI)) {
case HexagonII::MemAccessSize::DoubleWordAccess:
AlignMask = 0x7;
break;
case HexagonII::MemAccessSize::WordAccess:
AlignMask = 0x3;
break;
case HexagonII::MemAccessSize::HalfWordAccess:
AlignMask = 0x1;
break;
case HexagonII::MemAccessSize::ByteAccess:
AlignMask = 0x0;
break;
default:
return false;
}
if ((AlignMask & Offset) != 0)
return false;
return HII->isValidOffset(MI->getOpcode(), Offset, HRI, false);
}
bool HexagonOptAddrMode::processAddUses(NodeAddr<StmtNode *> AddSN,
MachineInstr *AddMI,
const NodeList &UNodeList) {
Register AddDefR = AddMI->getOperand(0).getReg();
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UN = *I;
NodeAddr<StmtNode *> SN = UN.Addr->getOwner(*DFG);
MachineInstr *MI = SN.Addr->getCode();
const MCInstrDesc &MID = MI->getDesc();
if ((!MID.mayLoad() && !MID.mayStore()) ||
HII->getAddrMode(*MI) != HexagonII::BaseImmOffset ||
HII->isHVXVec(*MI))
return false;
MachineOperand BaseOp = MID.mayLoad() ? MI->getOperand(1)
: MI->getOperand(0);
if (!BaseOp.isReg() || BaseOp.getReg() != AddDefR)
return false;
MachineOperand OffsetOp = MID.mayLoad() ? MI->getOperand(2)
: MI->getOperand(1);
if (!OffsetOp.isImm())
return false;
int64_t newOffset = OffsetOp.getImm() + AddMI->getOperand(2).getImm();
if (!isValidOffset(MI, newOffset))
return false;
// Since we'll be extending the live range of Rt in the following example,
// make sure that is safe. another definition of Rt doesn't exist between 'add'
// and load/store instruction.
//
// Ex: Rx= add(Rt,#10)
// memw(Rx+#0) = Rs
// will be replaced with => memw(Rt+#10) = Rs
Register BaseReg = AddMI->getOperand(1).getReg();
if (!isSafeToExtLR(AddSN, AddMI, BaseReg, UNodeList))
return false;
}
// Update all the uses of 'add' with the appropriate base and offset
// values.
bool Changed = false;
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UseN = *I;
assert(!(UseN.Addr->getFlags() & NodeAttrs::PhiRef) &&
"Found a PhiRef node as a real reached use!!");
NodeAddr<StmtNode *> OwnerN = UseN.Addr->getOwner(*DFG);
MachineInstr *UseMI = OwnerN.Addr->getCode();
LLVM_DEBUG(dbgs() << "\t\t[MI <BB#" << UseMI->getParent()->getNumber()
<< ">]: " << *UseMI << "\n");
Changed |= updateAddUses(AddMI, UseMI);
}
if (Changed)
Deleted.insert(AddMI);
return Changed;
}
bool HexagonOptAddrMode::updateAddUses(MachineInstr *AddMI,
MachineInstr *UseMI) {
const MachineOperand ImmOp = AddMI->getOperand(2);
const MachineOperand AddRegOp = AddMI->getOperand(1);
Register newReg = AddRegOp.getReg();
const MCInstrDesc &MID = UseMI->getDesc();
MachineOperand &BaseOp = MID.mayLoad() ? UseMI->getOperand(1)
: UseMI->getOperand(0);
MachineOperand &OffsetOp = MID.mayLoad() ? UseMI->getOperand(2)
: UseMI->getOperand(1);
BaseOp.setReg(newReg);
BaseOp.setIsUndef(AddRegOp.isUndef());
BaseOp.setImplicit(AddRegOp.isImplicit());
OffsetOp.setImm(ImmOp.getImm() + OffsetOp.getImm());
MRI->clearKillFlags(newReg);
return true;
}
bool HexagonOptAddrMode::analyzeUses(unsigned tfrDefR,
const NodeList &UNodeList,
InstrEvalMap &InstrEvalResult,
short &SizeInc) {
bool KeepTfr = false;
bool HasRepInstr = false;
InstrEvalResult.clear();
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
bool CanBeReplaced = false;
NodeAddr<UseNode *> UN = *I;
NodeAddr<StmtNode *> SN = UN.Addr->getOwner(*DFG);
MachineInstr &MI = *SN.Addr->getCode();
const MCInstrDesc &MID = MI.getDesc();
if ((MID.mayLoad() || MID.mayStore())) {
if (!hasRepForm(MI, tfrDefR)) {
KeepTfr = true;
continue;
}
SizeInc++;
CanBeReplaced = true;
} else if (MI.getOpcode() == Hexagon::S2_addasl_rrri) {
NodeList AddaslUseList;
LLVM_DEBUG(dbgs() << "\nGetting ReachedUses for === " << MI << "\n");
getAllRealUses(SN, AddaslUseList);
// Process phi nodes.
if (allValidCandidates(SN, AddaslUseList) &&
canRemoveAddasl(SN, MI, AddaslUseList)) {
SizeInc += AddaslUseList.size();
SizeInc -= 1; // Reduce size by 1 as addasl itself can be removed.
CanBeReplaced = true;
} else
SizeInc++;
} else
// Currently, only load/store and addasl are handled.
// Some other instructions to consider -
// A2_add -> A2_addi
// M4_mpyrr_addr -> M4_mpyrr_addi
KeepTfr = true;
InstrEvalResult[&MI] = CanBeReplaced;
HasRepInstr |= CanBeReplaced;
}
// Reduce total size by 2 if original tfr can be deleted.
if (!KeepTfr)
SizeInc -= 2;
return HasRepInstr;
}
bool HexagonOptAddrMode::changeLoad(MachineInstr *OldMI, MachineOperand ImmOp,
unsigned ImmOpNum) {
bool Changed = false;
MachineBasicBlock *BB = OldMI->getParent();
auto UsePos = MachineBasicBlock::iterator(OldMI);
MachineBasicBlock::instr_iterator InsertPt = UsePos.getInstrIterator();
++InsertPt;
unsigned OpStart;
unsigned OpEnd = OldMI->getNumOperands();
MachineInstrBuilder MIB;
if (ImmOpNum == 1) {
if (HII->getAddrMode(*OldMI) == HexagonII::BaseRegOffset) {
short NewOpCode = HII->changeAddrMode_rr_ur(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode));
MIB.add(OldMI->getOperand(0));
MIB.add(OldMI->getOperand(2));
MIB.add(OldMI->getOperand(3));
MIB.add(ImmOp);
OpStart = 4;
Changed = true;
} else if (HII->getAddrMode(*OldMI) == HexagonII::BaseImmOffset &&
OldMI->getOperand(2).isImm()) {
short NewOpCode = HII->changeAddrMode_io_abs(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode))
.add(OldMI->getOperand(0));
const GlobalValue *GV = ImmOp.getGlobal();
int64_t Offset = ImmOp.getOffset() + OldMI->getOperand(2).getImm();
MIB.addGlobalAddress(GV, Offset, ImmOp.getTargetFlags());
OpStart = 3;
Changed = true;
} else
Changed = false;
LLVM_DEBUG(dbgs() << "[Changing]: " << *OldMI << "\n");
LLVM_DEBUG(dbgs() << "[TO]: " << *MIB << "\n");
} else if (ImmOpNum == 2) {
if (OldMI->getOperand(3).isImm() && OldMI->getOperand(3).getImm() == 0) {
short NewOpCode = HII->changeAddrMode_rr_io(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode));
MIB.add(OldMI->getOperand(0));
MIB.add(OldMI->getOperand(1));
MIB.add(ImmOp);
OpStart = 4;
Changed = true;
LLVM_DEBUG(dbgs() << "[Changing]: " << *OldMI << "\n");
LLVM_DEBUG(dbgs() << "[TO]: " << *MIB << "\n");
}
}
if (Changed)
for (unsigned i = OpStart; i < OpEnd; ++i)
MIB.add(OldMI->getOperand(i));
return Changed;
}
bool HexagonOptAddrMode::changeStore(MachineInstr *OldMI, MachineOperand ImmOp,
unsigned ImmOpNum) {
bool Changed = false;
unsigned OpStart = 0;
unsigned OpEnd = OldMI->getNumOperands();
MachineBasicBlock *BB = OldMI->getParent();
auto UsePos = MachineBasicBlock::iterator(OldMI);
MachineBasicBlock::instr_iterator InsertPt = UsePos.getInstrIterator();
++InsertPt;
MachineInstrBuilder MIB;
if (ImmOpNum == 0) {
if (HII->getAddrMode(*OldMI) == HexagonII::BaseRegOffset) {
short NewOpCode = HII->changeAddrMode_rr_ur(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode));
MIB.add(OldMI->getOperand(1));
MIB.add(OldMI->getOperand(2));
MIB.add(ImmOp);
MIB.add(OldMI->getOperand(3));
OpStart = 4;
Changed = true;
} else if (HII->getAddrMode(*OldMI) == HexagonII::BaseImmOffset) {
short NewOpCode = HII->changeAddrMode_io_abs(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode));
const GlobalValue *GV = ImmOp.getGlobal();
int64_t Offset = ImmOp.getOffset() + OldMI->getOperand(1).getImm();
MIB.addGlobalAddress(GV, Offset, ImmOp.getTargetFlags());
MIB.add(OldMI->getOperand(2));
OpStart = 3;
Changed = true;
}
} else if (ImmOpNum == 1 && OldMI->getOperand(2).getImm() == 0) {
short NewOpCode = HII->changeAddrMode_rr_io(*OldMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
MIB = BuildMI(*BB, InsertPt, OldMI->getDebugLoc(), HII->get(NewOpCode));
MIB.add(OldMI->getOperand(0));
MIB.add(ImmOp);
OpStart = 3;
Changed = true;
}
if (Changed) {
LLVM_DEBUG(dbgs() << "[Changing]: " << *OldMI << "\n");
LLVM_DEBUG(dbgs() << "[TO]: " << *MIB << "\n");
for (unsigned i = OpStart; i < OpEnd; ++i)
MIB.add(OldMI->getOperand(i));
}
return Changed;
}
short HexagonOptAddrMode::getBaseWithLongOffset(const MachineInstr &MI) const {
if (HII->getAddrMode(MI) == HexagonII::BaseImmOffset) {
short TempOpCode = HII->changeAddrMode_io_rr(MI);
return HII->changeAddrMode_rr_ur(TempOpCode);
}
return HII->changeAddrMode_rr_ur(MI);
}
bool HexagonOptAddrMode::changeAddAsl(NodeAddr<UseNode *> AddAslUN,
MachineInstr *AddAslMI,
const MachineOperand &ImmOp,
unsigned ImmOpNum) {
NodeAddr<StmtNode *> SA = AddAslUN.Addr->getOwner(*DFG);
LLVM_DEBUG(dbgs() << "Processing addasl :" << *AddAslMI << "\n");
NodeList UNodeList;
getAllRealUses(SA, UNodeList);
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UseUN = *I;
assert(!(UseUN.Addr->getFlags() & NodeAttrs::PhiRef) &&
"Can't transform this 'AddAsl' instruction!");
NodeAddr<StmtNode *> UseIA = UseUN.Addr->getOwner(*DFG);
LLVM_DEBUG(dbgs() << "[InstrNode]: "
<< Print<NodeAddr<InstrNode *>>(UseIA, *DFG) << "\n");
MachineInstr *UseMI = UseIA.Addr->getCode();
LLVM_DEBUG(dbgs() << "[MI <" << printMBBReference(*UseMI->getParent())
<< ">]: " << *UseMI << "\n");
const MCInstrDesc &UseMID = UseMI->getDesc();
assert(HII->getAddrMode(*UseMI) == HexagonII::BaseImmOffset);
auto UsePos = MachineBasicBlock::iterator(UseMI);
MachineBasicBlock::instr_iterator InsertPt = UsePos.getInstrIterator();
short NewOpCode = getBaseWithLongOffset(*UseMI);
assert(NewOpCode >= 0 && "Invalid New opcode\n");
unsigned OpStart;
unsigned OpEnd = UseMI->getNumOperands();
MachineBasicBlock *BB = UseMI->getParent();
MachineInstrBuilder MIB =
BuildMI(*BB, InsertPt, UseMI->getDebugLoc(), HII->get(NewOpCode));
// change mem(Rs + # ) -> mem(Rt << # + ##)
if (UseMID.mayLoad()) {
MIB.add(UseMI->getOperand(0));
MIB.add(AddAslMI->getOperand(2));
MIB.add(AddAslMI->getOperand(3));
const GlobalValue *GV = ImmOp.getGlobal();
MIB.addGlobalAddress(GV, UseMI->getOperand(2).getImm()+ImmOp.getOffset(),
ImmOp.getTargetFlags());
OpStart = 3;
} else if (UseMID.mayStore()) {
MIB.add(AddAslMI->getOperand(2));
MIB.add(AddAslMI->getOperand(3));
const GlobalValue *GV = ImmOp.getGlobal();
MIB.addGlobalAddress(GV, UseMI->getOperand(1).getImm()+ImmOp.getOffset(),
ImmOp.getTargetFlags());
MIB.add(UseMI->getOperand(2));
OpStart = 3;
} else
llvm_unreachable("Unhandled instruction");
for (unsigned i = OpStart; i < OpEnd; ++i)
MIB.add(UseMI->getOperand(i));
Deleted.insert(UseMI);
}
return true;
}
bool HexagonOptAddrMode::xformUseMI(MachineInstr *TfrMI, MachineInstr *UseMI,
NodeAddr<UseNode *> UseN,
unsigned UseMOnum) {
const MachineOperand ImmOp = TfrMI->getOperand(1);
const MCInstrDesc &MID = UseMI->getDesc();
unsigned Changed = false;
if (MID.mayLoad())
Changed = changeLoad(UseMI, ImmOp, UseMOnum);
else if (MID.mayStore())
Changed = changeStore(UseMI, ImmOp, UseMOnum);
else if (UseMI->getOpcode() == Hexagon::S2_addasl_rrri)
Changed = changeAddAsl(UseN, UseMI, ImmOp, UseMOnum);
if (Changed)
Deleted.insert(UseMI);
return Changed;
}
bool HexagonOptAddrMode::processBlock(NodeAddr<BlockNode *> BA) {
bool Changed = false;
for (auto IA : BA.Addr->members(*DFG)) {
if (!DFG->IsCode<NodeAttrs::Stmt>(IA))
continue;
NodeAddr<StmtNode *> SA = IA;
MachineInstr *MI = SA.Addr->getCode();
if ((MI->getOpcode() != Hexagon::A2_tfrsi ||
!MI->getOperand(1).isGlobal()) &&
(MI->getOpcode() != Hexagon::A2_addi ||
!MI->getOperand(2).isImm() || HII->isConstExtended(*MI)))
continue;
LLVM_DEBUG(dbgs() << "[Analyzing " << HII->getName(MI->getOpcode())
<< "]: " << *MI << "\n\t[InstrNode]: "
<< Print<NodeAddr<InstrNode *>>(IA, *DFG) << '\n');
NodeList UNodeList;
getAllRealUses(SA, UNodeList);
if (!allValidCandidates(SA, UNodeList))
continue;
// Analyze all uses of 'add'. If the output of 'add' is used as an address
// in the base+immediate addressing mode load/store instructions, see if
// they can be updated to use the immediate value as an offet. Thus,
// providing us the opportunity to eliminate 'add'.
// Ex: Rx= add(Rt,#12)
// memw(Rx+#0) = Rs
// This can be replaced with memw(Rt+#12) = Rs
//
// This transformation is only performed if all uses can be updated and
// the offset isn't required to be constant extended.
if (MI->getOpcode() == Hexagon::A2_addi) {
Changed |= processAddUses(SA, MI, UNodeList);
continue;
}
short SizeInc = 0;
Register DefR = MI->getOperand(0).getReg();
InstrEvalMap InstrEvalResult;
// Analyze all uses and calculate increase in size. Perform the optimization
// only if there is no increase in size.
if (!analyzeUses(DefR, UNodeList, InstrEvalResult, SizeInc))
continue;
if (SizeInc > CodeGrowthLimit)
continue;
bool KeepTfr = false;
LLVM_DEBUG(dbgs() << "\t[Total reached uses] : " << UNodeList.size()
<< "\n");
LLVM_DEBUG(dbgs() << "\t[Processing Reached Uses] ===\n");
for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
NodeAddr<UseNode *> UseN = *I;
assert(!(UseN.Addr->getFlags() & NodeAttrs::PhiRef) &&
"Found a PhiRef node as a real reached use!!");
NodeAddr<StmtNode *> OwnerN = UseN.Addr->getOwner(*DFG);
MachineInstr *UseMI = OwnerN.Addr->getCode();
LLVM_DEBUG(dbgs() << "\t\t[MI <" << printMBBReference(*UseMI->getParent())
<< ">]: " << *UseMI << "\n");
int UseMOnum = -1;
unsigned NumOperands = UseMI->getNumOperands();
for (unsigned j = 0; j < NumOperands - 1; ++j) {
const MachineOperand &op = UseMI->getOperand(j);
if (op.isReg() && op.isUse() && DefR == op.getReg())
UseMOnum = j;
}
// It is possible that the register will not be found in any operand.
// This could happen, for example, when DefR = R4, but the used
// register is D2.
// Change UseMI if replacement is possible. If any replacement failed,
// or wasn't attempted, make sure to keep the TFR.
bool Xformed = false;
if (UseMOnum >= 0 && InstrEvalResult[UseMI])
Xformed = xformUseMI(MI, UseMI, UseN, UseMOnum);
Changed |= Xformed;
KeepTfr |= !Xformed;
}
if (!KeepTfr)
Deleted.insert(MI);
}
return Changed;
}
bool HexagonOptAddrMode::runOnMachineFunction(MachineFunction &MF) {
if (skipFunction(MF.getFunction()))
return false;
bool Changed = false;
auto &HST = MF.getSubtarget<HexagonSubtarget>();
MRI = &MF.getRegInfo();
HII = HST.getInstrInfo();
HRI = HST.getRegisterInfo();
const auto &MDF = getAnalysis<MachineDominanceFrontier>();
MDT = &getAnalysis<MachineDominatorTree>();
const TargetOperandInfo TOI(*HII);
DataFlowGraph G(MF, *HII, *HRI, *MDT, MDF, TOI);
// Need to keep dead phis because we can propagate uses of registers into
// nodes dominated by those would-be phis.
G.build(BuildOptions::KeepDeadPhis);
DFG = &G;
Liveness L(*MRI, *DFG);
L.computePhiInfo();
LV = &L;
Deleted.clear();
NodeAddr<FuncNode *> FA = DFG->getFunc();
LLVM_DEBUG(dbgs() << "==== [RefMap#]=====:\n "
<< Print<NodeAddr<FuncNode *>>(FA, *DFG) << "\n");
for (NodeAddr<BlockNode *> BA : FA.Addr->members(*DFG))
Changed |= processBlock(BA);
for (auto MI : Deleted)
MI->eraseFromParent();
if (Changed) {
G.build();
L.computeLiveIns();
L.resetLiveIns();
L.resetKills();
}
return Changed;
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
FunctionPass *llvm::createHexagonOptAddrMode() {
return new HexagonOptAddrMode();
}
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