- .addReg(DstReg, RegState::Define |
- getUndefRegState(SomeMI->getOperand(0).isUndef()),
- NewDstSubIdx)
- .addReg(SrcReg, 0, NewSrcSubIdx);
-
- // Remove all the old extract instructions.
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SrcReg),
- UE = MRI->use_nodbg_end(); UI != UE; ) {
- MachineInstr *UseMI = &*UI;
- ++UI;
- if (UseMI == CopyMI)
- continue;
- assert(UseMI->isCopy());
- // Move any kills to the new copy or extract instruction.
- if (UseMI->getOperand(1).isKill()) {
- CopyMI->getOperand(1).setIsKill();
- if (LV)
- // Update live variables
- LV->replaceKillInstruction(SrcReg, UseMI, &*CopyMI);
- }
- UseMI->eraseFromParent();
- }
- }
-}
-
-static bool HasOtherRegSequenceUses(unsigned Reg, MachineInstr *RegSeq,
- MachineRegisterInfo *MRI) {
- for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
- UE = MRI->use_end(); UI != UE; ++UI) {
- MachineInstr *UseMI = &*UI;
- if (UseMI != RegSeq && UseMI->isRegSequence())
- return true;
- }
- return false;
-}
-
-/// EliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
-/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
-/// sub-register references of the register defined by REG_SEQUENCE. e.g.
-///
-/// %reg1029<def>, %reg1030<def> = VLD1q16 %reg1024<kill>, ...
-/// %reg1031<def> = REG_SEQUENCE %reg1029<kill>, 5, %reg1030<kill>, 6
-/// =>
-/// %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ...
-bool TwoAddressInstructionPass::EliminateRegSequences() {
- if (RegSequences.empty())
- return false;
-
- for (unsigned i = 0, e = RegSequences.size(); i != e; ++i) {
- MachineInstr *MI = RegSequences[i];
- unsigned DstReg = MI->getOperand(0).getReg();
- if (MI->getOperand(0).getSubReg() ||
- TargetRegisterInfo::isPhysicalRegister(DstReg) ||
- !(MI->getNumOperands() & 1)) {
- DEBUG(dbgs() << "Illegal REG_SEQUENCE instruction:" << *MI);
- llvm_unreachable(0);
- }
-
- bool IsImpDef = true;
- SmallVector<unsigned, 4> RealSrcs;
- SmallSet<unsigned, 4> Seen;
- for (unsigned i = 1, e = MI->getNumOperands(); i < e; i += 2) {
- // Nothing needs to be inserted for <undef> operands.
- if (MI->getOperand(i).isUndef()) {
- MI->getOperand(i).setReg(0);
- continue;
- }
- unsigned SrcReg = MI->getOperand(i).getReg();
- unsigned SrcSubIdx = MI->getOperand(i).getSubReg();
- unsigned SubIdx = MI->getOperand(i+1).getImm();
- // DefMI of NULL means the value does not have a vreg in this block
- // i.e., its a physical register or a subreg.
- // In either case we force a copy to be generated.
- MachineInstr *DefMI = NULL;
- if (!MI->getOperand(i).getSubReg() &&
- !TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
- DefMI = MRI->getUniqueVRegDef(SrcReg);
- }
-
- if (DefMI && DefMI->isImplicitDef()) {
- DefMI->eraseFromParent();
- continue;
- }
- IsImpDef = false;
-
- // Remember COPY sources. These might be candidate for coalescing.
- if (DefMI && DefMI->isCopy() && DefMI->getOperand(1).getSubReg())
- RealSrcs.push_back(DefMI->getOperand(1).getReg());
-
- bool isKill = MI->getOperand(i).isKill();
- if (!DefMI || !Seen.insert(SrcReg) ||
- MI->getParent() != DefMI->getParent() ||
- !isKill || HasOtherRegSequenceUses(SrcReg, MI, MRI) ||
- !TRI->getMatchingSuperRegClass(MRI->getRegClass(DstReg),
- MRI->getRegClass(SrcReg), SubIdx)) {
- // REG_SEQUENCE cannot have duplicated operands, add a copy.
- // Also add an copy if the source is live-in the block. We don't want
- // to end up with a partial-redef of a livein, e.g.
- // BB0:
- // reg1051:10<def> =
- // ...
- // BB1:
- // ... = reg1051:10
- // BB2:
- // reg1051:9<def> =
- // LiveIntervalAnalysis won't like it.
- //
- // If the REG_SEQUENCE doesn't kill its source, keeping live variables
- // correctly up to date becomes very difficult. Insert a copy.
-
- // Defer any kill flag to the last operand using SrcReg. Otherwise, we
- // might insert a COPY that uses SrcReg after is was killed.
- if (isKill)
- for (unsigned j = i + 2; j < e; j += 2)
- if (MI->getOperand(j).getReg() == SrcReg) {
- MI->getOperand(j).setIsKill();
- isKill = false;
- break;
- }
-
- MachineBasicBlock::iterator InsertLoc = MI;
- MachineInstr *CopyMI = BuildMI(*MI->getParent(), InsertLoc,
- MI->getDebugLoc(), TII->get(TargetOpcode::COPY))
- .addReg(DstReg, RegState::Define, SubIdx)
- .addReg(SrcReg, getKillRegState(isKill), SrcSubIdx);
- MI->getOperand(i).setReg(0);
- if (LV && isKill && !TargetRegisterInfo::isPhysicalRegister(SrcReg))
- LV->replaceKillInstruction(SrcReg, MI, CopyMI);
- DEBUG(dbgs() << "Inserted: " << *CopyMI);
- }