- // Handle physreg joins separately.
- if (CP.isPhys())
- return joinReservedPhysReg(CP);
-
- if (NewCoalescer)
- return joinVirtRegs(CP);
-
- LiveInterval &RHS = LIS->getInterval(CP.getSrcReg());
- DEBUG(dbgs() << "\t\tRHS = " << PrintReg(CP.getSrcReg()) << ' ' << RHS
- << '\n');
-
- // Compute the final value assignment, assuming that the live ranges can be
- // coalesced.
- SmallVector<int, 16> LHSValNoAssignments;
- SmallVector<int, 16> RHSValNoAssignments;
- DenseMap<VNInfo*, VNInfo*> LHSValsDefinedFromRHS;
- DenseMap<VNInfo*, VNInfo*> RHSValsDefinedFromLHS;
- SmallVector<VNInfo*, 16> NewVNInfo;
-
- SmallVector<MachineInstr*, 8> DupCopies;
- SmallVector<MachineInstr*, 8> DeadCopies;
-
- LiveInterval &LHS = LIS->getOrCreateInterval(CP.getDstReg());
- DEBUG(dbgs() << "\t\tLHS = " << PrintReg(CP.getDstReg(), TRI) << ' ' << LHS
- << '\n');
-
- // Loop over the value numbers of the LHS, seeing if any are defined from
- // the RHS.
- for (LiveInterval::vni_iterator i = LHS.vni_begin(), e = LHS.vni_end();
- i != e; ++i) {
- VNInfo *VNI = *i;
- if (VNI->isUnused() || VNI->isPHIDef())
- continue;
- MachineInstr *MI = LIS->getInstructionFromIndex(VNI->def);
- assert(MI && "Missing def");
- if (!MI->isCopyLike() && !MI->isImplicitDef()) // Src not defined by a copy?
- continue;
-
- // Figure out the value # from the RHS.
- VNInfo *OtherVNI = RHS.getVNInfoBefore(VNI->def);
- // The copy could be to an aliased physreg.
- if (!OtherVNI)
- continue;
-
- // DstReg is known to be a register in the LHS interval. If the src is
- // from the RHS interval, we can use its value #.
- if (CP.isCoalescable(MI))
- DeadCopies.push_back(MI);
- else if (!RegistersDefinedFromSameValue(*LIS, *TRI, CP, VNI, OtherVNI,
- DupCopies))
- continue;
-
- LHSValsDefinedFromRHS[VNI] = OtherVNI;
- }
-
- // Loop over the value numbers of the RHS, seeing if any are defined from
- // the LHS.
- for (LiveInterval::vni_iterator i = RHS.vni_begin(), e = RHS.vni_end();
- i != e; ++i) {
- VNInfo *VNI = *i;
- if (VNI->isUnused() || VNI->isPHIDef())
- continue;
- MachineInstr *MI = LIS->getInstructionFromIndex(VNI->def);
- assert(MI && "Missing def");
- if (!MI->isCopyLike() && !MI->isImplicitDef()) // Src not defined by a copy?
- continue;
-
- // Figure out the value # from the LHS.
- VNInfo *OtherVNI = LHS.getVNInfoBefore(VNI->def);
- // The copy could be to an aliased physreg.
- if (!OtherVNI)
- continue;
-
- // DstReg is known to be a register in the RHS interval. If the src is
- // from the LHS interval, we can use its value #.
- if (CP.isCoalescable(MI))
- DeadCopies.push_back(MI);
- else if (!RegistersDefinedFromSameValue(*LIS, *TRI, CP, VNI, OtherVNI,
- DupCopies))
- continue;
-
- RHSValsDefinedFromLHS[VNI] = OtherVNI;
- }
-
- LHSValNoAssignments.resize(LHS.getNumValNums(), -1);
- RHSValNoAssignments.resize(RHS.getNumValNums(), -1);
- NewVNInfo.reserve(LHS.getNumValNums() + RHS.getNumValNums());
-
- for (LiveInterval::vni_iterator i = LHS.vni_begin(), e = LHS.vni_end();
- i != e; ++i) {
- VNInfo *VNI = *i;
- unsigned VN = VNI->id;
- if (LHSValNoAssignments[VN] >= 0 || VNI->isUnused())
- continue;
- ComputeUltimateVN(VNI, NewVNInfo,
- LHSValsDefinedFromRHS, RHSValsDefinedFromLHS,
- LHSValNoAssignments, RHSValNoAssignments);
- }
- for (LiveInterval::vni_iterator i = RHS.vni_begin(), e = RHS.vni_end();
- i != e; ++i) {
- VNInfo *VNI = *i;
- unsigned VN = VNI->id;
- if (RHSValNoAssignments[VN] >= 0 || VNI->isUnused())
- continue;
- // If this value number isn't a copy from the LHS, it's a new number.
- if (RHSValsDefinedFromLHS.find(VNI) == RHSValsDefinedFromLHS.end()) {
- NewVNInfo.push_back(VNI);
- RHSValNoAssignments[VN] = NewVNInfo.size()-1;
- continue;
- }
-
- ComputeUltimateVN(VNI, NewVNInfo,
- RHSValsDefinedFromLHS, LHSValsDefinedFromRHS,
- RHSValNoAssignments, LHSValNoAssignments);
- }
-
- // Armed with the mappings of LHS/RHS values to ultimate values, walk the
- // interval lists to see if these intervals are coalescable.
- LiveInterval::const_iterator I = LHS.begin();
- LiveInterval::const_iterator IE = LHS.end();
- LiveInterval::const_iterator J = RHS.begin();
- LiveInterval::const_iterator JE = RHS.end();
-
- // Collect interval end points that will no longer be kills.
- SmallVector<MachineInstr*, 8> LHSOldKills;
- SmallVector<MachineInstr*, 8> RHSOldKills;
-
- // Skip ahead until the first place of potential sharing.
- if (I != IE && J != JE) {
- if (I->start < J->start) {
- I = std::upper_bound(I, IE, J->start);
- if (I != LHS.begin()) --I;
- } else if (J->start < I->start) {
- J = std::upper_bound(J, JE, I->start);
- if (J != RHS.begin()) --J;
- }
- }
-
- while (I != IE && J != JE) {
- // Determine if these two live ranges overlap.
- // If so, check value # info to determine if they are really different.
- if (I->end > J->start && J->end > I->start) {
- // If the live range overlap will map to the same value number in the
- // result liverange, we can still coalesce them. If not, we can't.
- if (LHSValNoAssignments[I->valno->id] !=
- RHSValNoAssignments[J->valno->id])
- return false;
-
- // Extended live ranges should no longer be killed.
- if (!I->end.isBlock() && I->end < J->end)
- if (MachineInstr *MI = LIS->getInstructionFromIndex(I->end))
- LHSOldKills.push_back(MI);
- if (!J->end.isBlock() && J->end < I->end)
- if (MachineInstr *MI = LIS->getInstructionFromIndex(J->end))
- RHSOldKills.push_back(MI);
- }
-
- if (I->end < J->end)
- ++I;
- else
- ++J;
- }