#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/BitVector.h"
STATISTIC(Num3AddrSunk, "Number of 3-address instructions sunk");
STATISTIC(NumReMats, "Number of instructions re-materialized");
-static cl::opt<bool>
-EnableReMat("two-addr-remat", cl::init(false), cl::Hidden,
- cl::desc("Two-addr conversion should remat when possible."));
-
namespace {
class VISIBILITY_HIDDEN TwoAddressInstructionPass
: public MachineFunctionPass {
bool isSafeToReMat(unsigned DstReg, MachineInstr *MI);
bool isProfitableToReMat(unsigned Reg, const TargetRegisterClass *RC,
- MachineInstr *MI, unsigned Loc,
- MachineInstr *DefMI, MachineBasicBlock *MBB,
+ MachineInstr *MI, MachineInstr *DefMI,
+ MachineBasicBlock *MBB, unsigned Loc,
DenseMap<MachineInstr*, unsigned> &DistanceMap);
public:
static char ID; // Pass identification, replacement for typeid
TwoAddressInstructionPass() : MachineFunctionPass((intptr_t)&ID) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<LiveVariables>();
AU.addPreserved<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
KillMO->setIsKill(false);
KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI);
KillMO->setIsKill(true);
- LiveVariables::VarInfo& VarInfo = LV->getVarInfo(SavedReg);
- VarInfo.removeKill(KillMI);
- VarInfo.Kills.push_back(MI);
+
+ if (LV)
+ LV->replaceKillInstruction(SavedReg, KillMI, MI);
// Move instruction to its destination.
MBB->remove(MI);
const TargetInstrDesc &TID = UseMI->getDesc();
for (unsigned i = 0, e = TID.getNumOperands(); i != e; ++i) {
MachineOperand &MO = UseMI->getOperand(i);
- if (MO.getReg() == Reg &&
+ if (MO.isRegister() && MO.getReg() == Reg &&
(MO.isDef() || TID.getOperandConstraint(i, TOI::TIED_TO) != -1))
// Earlier use is a two-address one.
return true;
bool
TwoAddressInstructionPass::isProfitableToReMat(unsigned Reg,
const TargetRegisterClass *RC,
- MachineInstr *MI, unsigned Loc,
- MachineInstr *DefMI, MachineBasicBlock *MBB,
- DenseMap<MachineInstr*, unsigned> &DistanceMap) {
- if (DefMI->getParent() != MBB)
- return true;
- // If earlier uses in MBB are not two-address uses, then don't remat.
+ MachineInstr *MI, MachineInstr *DefMI,
+ MachineBasicBlock *MBB, unsigned Loc,
+ DenseMap<MachineInstr*, unsigned> &DistanceMap){
bool OtherUse = false;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
UE = MRI->use_end(); UI != UE; ++UI) {
if (!UseMO.isUse())
continue;
MachineInstr *UseMI = UseMO.getParent();
- if (UseMI->getParent() != MBB)
- continue;
- DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI);
- if (DI != DistanceMap.end() && DI->second == Loc)
- continue; // Current use.
- OtherUse = true;
- // There is at least one other use in the MBB that will clobber the
- // register.
- if (isTwoAddrUse(UseMI, Reg))
- return true;
+ MachineBasicBlock *UseMBB = UseMI->getParent();
+ if (UseMBB == MBB) {
+ DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI);
+ if (DI != DistanceMap.end() && DI->second == Loc)
+ continue; // Current use.
+ OtherUse = true;
+ // There is at least one other use in the MBB that will clobber the
+ // register.
+ if (isTwoAddrUse(UseMI, Reg))
+ return true;
+ }
}
- return !OtherUse;
+
+ // If other uses in MBB are not two-address uses, then don't remat.
+ if (OtherUse)
+ return false;
+
+ // No other uses in the same block, remat if it's defined in the same
+ // block so it does not unnecessarily extend the live range.
+ return MBB == DefMI->getParent();
}
/// runOnMachineFunction - Reduce two-address instructions to two operands.
MRI = &MF.getRegInfo();
TII = TM.getInstrInfo();
TRI = TM.getRegisterInfo();
- LV = &getAnalysis<LiveVariables>();
+ LV = getAnalysisToUpdate<LiveVariables>();
bool MadeChange = false;
DOUT << "2addr: COMMUTED TO: " << *NewMI;
// If the instruction changed to commute it, update livevar.
if (NewMI != mi) {
- LV->instructionChanged(mi, NewMI); // Update live variables
+ if (LV)
+ // Update live variables
+ LV->replaceKillInstruction(regC, mi, NewMI);
+
mbbi->insert(mi, NewMI); // Insert the new inst
mbbi->erase(mi); // Nuke the old inst.
mi = NewMI;
assert(TID.getOperandConstraint(i, TOI::TIED_TO) == -1);
#endif
- MachineInstr *NewMI = TII->convertToThreeAddress(mbbi, mi, *LV);
+ MachineInstr *NewMI = TII->convertToThreeAddress(mbbi, mi, LV);
if (NewMI) {
DOUT << "2addr: CONVERTING 2-ADDR: " << *mi;
DOUT << "2addr: TO 3-ADDR: " << *NewMI;
MachineInstr *DefMI = MRI->getVRegDef(regB);
// If it's safe and profitable, remat the definition instead of
// copying it.
- if (EnableReMat && DefMI &&
+ if (DefMI &&
isSafeToReMat(regB, DefMI) &&
- isProfitableToReMat(regB, rc, mi, Dist, DefMI, mbbi,DistanceMap)){
+ isProfitableToReMat(regB, rc, mi, DefMI, mbbi, Dist,DistanceMap)){
DEBUG(cerr << "2addr: REMATTING : " << *DefMI << "\n");
TII->reMaterialize(*mbbi, mi, regA, DefMI);
ReMatRegs.set(regB);
DOUT << "\t\tprepend:\t"; DEBUG(prevMi->print(*cerr.stream(), &TM));
// Update live variables for regB.
- LiveVariables::VarInfo& varInfoB = LV->getVarInfo(regB);
-
- // regB is used in this BB.
- varInfoB.UsedBlocks[mbbi->getNumber()] = true;
+ if (LV) {
+ LiveVariables::VarInfo& varInfoB = LV->getVarInfo(regB);
- if (LV->removeVirtualRegisterKilled(regB, mbbi, mi))
- LV->addVirtualRegisterKilled(regB, prevMi);
+ // regB is used in this BB.
+ varInfoB.UsedBlocks[mbbi->getNumber()] = true;
- if (LV->removeVirtualRegisterDead(regB, mbbi, mi))
- LV->addVirtualRegisterDead(regB, prevMi);
+ if (LV->removeVirtualRegisterKilled(regB, mi))
+ LV->addVirtualRegisterKilled(regB, prevMi);
+ if (LV->removeVirtualRegisterDead(regB, mi))
+ LV->addVirtualRegisterDead(regB, prevMi);
+ }
+
// Replace all occurences of regB with regA.
for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
if (mi->getOperand(i).isRegister() &&
}
}
- if (EnableReMat) {
- // Some remat'ed instructions are dead.
- int VReg = ReMatRegs.find_first();
- while (VReg != -1) {
- if (MRI->use_empty(VReg)) {
- MachineInstr *DefMI = MRI->getVRegDef(VReg);
- DefMI->eraseFromParent();
- }
- VReg = ReMatRegs.find_next(VReg);
+ // Some remat'ed instructions are dead.
+ int VReg = ReMatRegs.find_first();
+ while (VReg != -1) {
+ if (MRI->use_empty(VReg)) {
+ MachineInstr *DefMI = MRI->getVRegDef(VReg);
+ DefMI->eraseFromParent();
}
-
+ VReg = ReMatRegs.find_next(VReg);
}
return MadeChange;
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