diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/DeadMachineInstructionElim.cpp | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp index 5b2e31ab42..f5ca2d470a 100644 --- a/lib/CodeGen/DeadMachineInstructionElim.cpp +++ b/lib/CodeGen/DeadMachineInstructionElim.cpp @@ -33,6 +33,7 @@ namespace { const MachineRegisterInfo *MRI; const TargetInstrInfo *TII; BitVector LivePhysRegs; + BitVector ReservedRegs; public: static char ID; // Pass identification, replacement for typeid @@ -67,10 +68,14 @@ bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const { const MachineOperand &MO = MI->getOperand(i); if (MO.isReg() && MO.isDef()) { unsigned Reg = MO.getReg(); - if (TargetRegisterInfo::isPhysicalRegister(Reg) ? - LivePhysRegs[Reg] : !MRI->use_nodbg_empty(Reg)) { - // This def has a non-debug use. Don't delete the instruction! - return false; + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { + // Don't delete live physreg defs, or any reserved register defs. + if (LivePhysRegs.test(Reg) || ReservedRegs.test(Reg)) + return false; + } else { + if (!MRI->use_nodbg_empty(Reg)) + // This def has a non-debug use. Don't delete the instruction! + return false; } } } @@ -86,7 +91,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) { TII = MF.getTarget().getInstrInfo(); // Treat reserved registers as always live. - BitVector ReservedRegs = TRI->getReservedRegs(MF); + ReservedRegs = TRI->getReservedRegs(MF); // Loop over all instructions in all blocks, from bottom to top, so that it's // more likely that chains of dependent but ultimately dead instructions will @@ -173,7 +178,6 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) { } else if (MO.isRegMask()) { // Register mask of preserved registers. All clobbers are dead. LivePhysRegs.clearBitsNotInMask(MO.getRegMask()); - LivePhysRegs |= ReservedRegs; } } // Record the physreg uses, after the defs, in case a physreg is |