diff options
Diffstat (limited to 'lib/CodeGen/DeadMachineInstructionElim.cpp')
| -rw-r--r-- | lib/CodeGen/DeadMachineInstructionElim.cpp | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp index 318d922adebf..fdc1d9142140 100644 --- a/lib/CodeGen/DeadMachineInstructionElim.cpp +++ b/lib/CodeGen/DeadMachineInstructionElim.cpp @@ -36,7 +36,9 @@ namespace { public: static char ID; // Pass identification, replacement for typeid - DeadMachineInstructionElim() : MachineFunctionPass(ID) {} + DeadMachineInstructionElim() : MachineFunctionPass(ID) { + initializeDeadMachineInstructionElimPass(*PassRegistry::getPassRegistry()); + } private: bool isDead(const MachineInstr *MI) const; @@ -45,13 +47,19 @@ namespace { char DeadMachineInstructionElim::ID = 0; INITIALIZE_PASS(DeadMachineInstructionElim, "dead-mi-elimination", - "Remove dead machine instructions", false, false); + "Remove dead machine instructions", false, false) FunctionPass *llvm::createDeadMachineInstructionElimPass() { return new DeadMachineInstructionElim(); } bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const { + // Technically speaking inline asm without side effects and no defs can still + // be deleted. But there is so much bad inline asm code out there, we should + // let them be. + if (MI->isInlineAsm()) + return false; + // Don't delete instructions with side effects. bool SawStore = false; if (!MI->isSafeToMove(TII, 0, SawStore) && !MI->isPHI()) @@ -151,7 +159,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) { const MachineOperand &MO = MI->getOperand(i); if (MO.isReg() && MO.isDef()) { unsigned Reg = MO.getReg(); - if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg)) { + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { LivePhysRegs.reset(Reg); // Check the subreg set, not the alias set, because a def // of a super-register may still be partially live after @@ -168,7 +176,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) { const MachineOperand &MO = MI->getOperand(i); if (MO.isReg() && MO.isUse()) { unsigned Reg = MO.getReg(); - if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg)) { + if (TargetRegisterInfo::isPhysicalRegister(Reg)) { LivePhysRegs.set(Reg); for (const unsigned *AliasSet = TRI->getAliasSet(Reg); *AliasSet; ++AliasSet) |