[LLVMdev] PR1350 (Vreg subregs) questions

[Chris Lattner]

On Wed, 13 Jun 2007, Christopher Lamb wrote:
>>  Where would you use this?  It seems that the only place that would need it
>>  is in the DAG schedulers, which turn the dags into a machineinstr stream.
>>  If so, putting it into the scheduler baseclass would make sense.
>
> It gets used in MachineInstrBuilder, MachineInstr, MRegisterInfo, and 
> ScheduleDAG. Basically any place where a vreg currently gets passed around by 
> an unsigned needs to accept the pair. In my working copy I've split it out 
> into it's own header file to reduce extraneous includes.

Ok, I suggest putting it in MachineInstr.h then.

>>  If you do something like this, I'd suggest a trivial value class that
>>  doesn't derive from std::pair.
>
> By a value class do you mean a subclass of Value or just a class with no 
> superclass?

Just a class with no superclass :)

-Chris

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