[LLVMdev] Bug in LiveIntervals? Please Examine

[Evan Cheng]

On Jul 17, 2009, at 7:57 AM, David Greene wrote:

> In LiveIntervals::processImplicitDefs() we have this:
>
>      for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(Reg),
>             UE = mri_->use_end(); UI != UE; ) {
>        MachineOperand &RMO = UI.getOperand();
>        MachineInstr *RMI = &*UI;
>        ++UI;
>        MachineBasicBlock *RMBB = RMI->getParent();
>        if (RMBB == MBB)
>          continue;
>        const TargetRegisterClass* RC = mri_->getRegClass(Reg);
>        unsigned NewVReg = mri_->createVirtualRegister(RC);
>        MachineInstrBuilder MIB =
>          BuildMI(*RMBB, RMI, RMI->getDebugLoc(),
>                  tii_->get(TargetInstrInfo::IMPLICIT_DEF), NewVReg);
>        (*MIB).getOperand(0).setIsUndef();
>        RMO.setReg(NewVReg);
>        RMO.setIsUndef();
>        RMO.setIsKill();
>      }
>
> Souldn't there be a call to vrm.grow() after each call to
> mri->createVirtualRegister()?

No. This function is run during the analysis stage. vrm is actually  
owned by the register allocator which then passed it into  
liveintervals. Is there an actual problem that you run into?

Evan

>
>                            -Dave
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