Index: lib/CodeGen/SelectionDAG/InstrEmitter.cpp =================================================================== --- lib/CodeGen/SelectionDAG/InstrEmitter.cpp +++ lib/CodeGen/SelectionDAG/InstrEmitter.cpp @@ -694,6 +694,20 @@ assert(cast(Var)->isValidLocationForIntrinsic(DL) && "Expected inlined-at fields to agree"); + SD->setIsEmitted(); + + if (SD->isInvalidated()) { + // An invalidated SDNode must generate an undef DBG_VALUE: although the + // original value is no longer computed, earlier DBG_VALUEs live ranges + // must be prevented from leaking into later code. + auto MIB = BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE)); + MIB.addReg(0U); + MIB.addReg(0U, RegState::Debug); + MIB.addMetadata(Var); + MIB.addMetadata(Expr); + return &*MIB; + } + if (SD->getKind() == SDDbgValue::FRAMEIX) { // Stack address; this needs to be lowered in target-dependent fashion. // EmitTargetCodeForFrameDebugValue is responsible for allocation. Index: lib/CodeGen/SelectionDAG/SDNodeDbgValue.h =================================================================== --- lib/CodeGen/SelectionDAG/SDNodeDbgValue.h +++ lib/CodeGen/SelectionDAG/SDNodeDbgValue.h @@ -53,6 +53,7 @@ enum DbgValueKind kind; bool IsIndirect; bool Invalid = false; + bool Emitted = false; public: /// Constructor for non-constants. @@ -126,6 +127,15 @@ void setIsInvalidated() { Invalid = true; } bool isInvalidated() const { return Invalid; } + /// setIsEmitted / isEmitted - Getter/Setter for flag indicating that this + /// SDDbgValue has been emitted to an MBB. + void setIsEmitted() { Emitted = true; } + bool isEmitted() const { return Emitted; } + + /// clearIsEmitted - Reset Emitted flag, for certain special cases where + /// dbg.addr is emitted twice. + void clearIsEmitted() { Emitted = false; } + LLVM_DUMP_METHOD void dump(raw_ostream &OS) const; }; Index: lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp =================================================================== --- lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp +++ lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp @@ -776,11 +776,9 @@ if (N->getHasDebugValue()) { MachineBasicBlock::iterator InsertPos = Emitter.getInsertPos(); for (auto DV : DAG->GetDbgValues(N)) { - if (DV->isInvalidated()) - continue; - if (auto *DbgMI = Emitter.EmitDbgValue(DV, VRBaseMap)) - BB->insert(InsertPos, DbgMI); - DV->setIsInvalidated(); + if (!DV->isEmitted()) + if (auto *DbgMI = Emitter.EmitDbgValue(DV, VRBaseMap)) + BB->insert(InsertPos, DbgMI); } } } Index: lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp =================================================================== --- lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp +++ lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp @@ -722,7 +722,7 @@ MachineBasicBlock *BB = Emitter.getBlock(); MachineBasicBlock::iterator InsertPos = Emitter.getInsertPos(); for (auto DV : DAG->GetDbgValues(N)) { - if (DV->isInvalidated()) + if (DV->isEmitted()) continue; unsigned DVOrder = DV->getOrder(); if (!Order || DVOrder == Order) { @@ -731,7 +731,6 @@ Orders.push_back({DVOrder, DbgMI}); BB->insert(InsertPos, DbgMI); } - DV->setIsInvalidated(); } } } @@ -822,8 +821,10 @@ SDDbgInfo::DbgIterator PDE = DAG->ByvalParmDbgEnd(); for (; PDI != PDE; ++PDI) { MachineInstr *DbgMI= Emitter.EmitDbgValue(*PDI, VRBaseMap); - if (DbgMI) + if (DbgMI) { BB->insert(InsertPos, DbgMI); + (*PDI)->clearIsEmitted(); + } } } @@ -889,7 +890,7 @@ for (; DI != DE; ++DI) { if ((*DI)->getOrder() < LastOrder || (*DI)->getOrder() >= Order) break; - if ((*DI)->isInvalidated()) + if ((*DI)->isEmitted()) continue; MachineInstr *DbgMI = Emitter.EmitDbgValue(*DI, VRBaseMap); @@ -911,7 +912,7 @@ // some of them before one or more conditional branches? SmallVector DbgMIs; for (; DI != DE; ++DI) { - if ((*DI)->isInvalidated()) + if ((*DI)->isEmitted()) continue; assert((*DI)->getOrder() >= LastOrder && "emitting DBG_VALUE out of order"); Index: lib/CodeGen/SelectionDAG/SelectionDAG.cpp =================================================================== --- lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -7742,8 +7742,10 @@ Dbg->getDebugLoc(), Dbg->getOrder()); ClonedDVs.push_back(Clone); - if (InvalidateDbg) + if (InvalidateDbg) { Dbg->setIsInvalidated(); + Dbg->setIsEmitted(); + } } for (SDDbgValue *Dbg : ClonedDVs) @@ -7780,6 +7782,7 @@ DV->isIndirect(), DV->getDebugLoc(), DV->getOrder()); ClonedDVs.push_back(Clone); DV->setIsInvalidated(); + DV->setIsEmitted(); LLVM_DEBUG(dbgs() << "SALVAGE: Rewriting"; N0.getNode()->dumprFull(this); dbgs() << " into " << *DIExpr << '\n');