[llvm] r175604 - Add support to the two-address pass for updating LiveIntervals in many of the

[Jakob Stoklund Olesen]

On Feb 20, 2013, at 2:25 PM, Cameron Zwarich <zwarich at apple.com> wrote:

> On Feb 20, 2013, at 9:03 AM, Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote:
> 
>>> +  // Udpate LiveIntervals.
>>> +  if (LIS) {
>>> +    if (MBBI != MBB->begin())
>>> +      --MBBI;
>>> +    LIS->repairIntervalsInRange(MBB, MBBI, EndMBBI, OrigRegs);
>>> +  }
>> 
>> This looks odd to me.
>> 
>> If it is correct to not decrement MBBI at begin(), shouldn't it be safe to always always skip the decrement?
>> 
>> Also, wouldn't it be easier if repairIntervalsInRange() did it's own reversing, instead of making all the callers do it?
>> 
>> What exactly is the meaning of the range passed to repairIntervalsInRange()? Could you describe that in the function declaration's comment, please?
>> 
>> It would be natural to me if you passed it just the range of new or changed instructions. If the algorithm needs to find anchor points, that should be a hidden implementation detail.
> 
> I fixed this (and the SlotIndexes case) in r175673. I should probably still add comments explaining their meaning.

Thanks.

A comment would still be useful.

/jakob