diff options
Diffstat (limited to 'lib/CodeGen/LiveVariables.cpp')
-rw-r--r-- | lib/CodeGen/LiveVariables.cpp | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp index bfc2d08528..68f80acf15 100644 --- a/lib/CodeGen/LiveVariables.cpp +++ b/lib/CodeGen/LiveVariables.cpp @@ -279,6 +279,43 @@ void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) { PhysRegUse[SubReg] = MI; } +/// FindLastRefOrPartRef - Return the last reference or partial reference of +/// the specified register. +MachineInstr *LiveVariables::FindLastRefOrPartRef(unsigned Reg) { + MachineInstr *LastDef = PhysRegDef[Reg]; + MachineInstr *LastUse = PhysRegUse[Reg]; + if (!LastDef && !LastUse) + return false; + + MachineInstr *LastRefOrPartRef = LastUse ? LastUse : LastDef; + unsigned LastRefOrPartRefDist = DistanceMap[LastRefOrPartRef]; + MachineInstr *LastPartDef = 0; + unsigned LastPartDefDist = 0; + for (const unsigned *SubRegs = TRI->getSubRegisters(Reg); + unsigned SubReg = *SubRegs; ++SubRegs) { + MachineInstr *Def = PhysRegDef[SubReg]; + if (Def && Def != LastDef) { + // There was a def of this sub-register in between. This is a partial + // def, keep track of the last one. + unsigned Dist = DistanceMap[Def]; + if (Dist > LastPartDefDist) { + LastPartDefDist = Dist; + LastPartDef = Def; + } + continue; + } + if (MachineInstr *Use = PhysRegUse[SubReg]) { + unsigned Dist = DistanceMap[Use]; + if (Dist > LastRefOrPartRefDist) { + LastRefOrPartRefDist = Dist; + LastRefOrPartRef = Use; + } + } + } + + return LastRefOrPartRef; +} + bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *MI) { MachineInstr *LastDef = PhysRegDef[Reg]; MachineInstr *LastUse = PhysRegUse[Reg]; @@ -373,7 +410,16 @@ bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *MI) { if (NeedDef) PhysRegDef[Reg]->addOperand(MachineOperand::CreateReg(SubReg, true/*IsDef*/, true/*IsImp*/)); - LastRefOrPartRef->addRegisterKilled(SubReg, TRI, true); + MachineInstr *LastSubRef = FindLastRefOrPartRef(SubReg); + if (LastSubRef) + LastSubRef->addRegisterKilled(SubReg, TRI, true); + else { + LastRefOrPartRef->addRegisterKilled(SubReg, TRI, true); + PhysRegUse[SubReg] = LastRefOrPartRef; + for (const unsigned *SSRegs = TRI->getSubRegisters(SubReg); + unsigned SSReg = *SSRegs; ++SSRegs) + PhysRegUse[SSReg] = LastRefOrPartRef; + } for (const unsigned *SS = TRI->getSubRegisters(SubReg); *SS; ++SS) PartUses.erase(*SS); } |