[llvm-commits] [llvm] r155364 - in /llvm/trunk: include/llvm/CodeGen/DFAPacketizer.h lib/CodeGen/DFAPacketizer.cpp

[Andrew Trick]

On Apr 24, 2012, at 7:54 AM, Sirish Pande <spande at codeaurora.org> wrote:

> On 4/23/2012 3:26 PM, Andrew Trick wrote:
>> 
>> 
>> On Apr 23, 2012, at 11:55 AM, Sirish Pande <spande at codeaurora.org> wrote:
>> 
>> +  VLIWScheduler->exitRegion();
>> 
>> I'm not sure why you would do this *before* packetizing. It's ok if it works, just a little misleading. You should probably add a call to VLIWScheduler->finishBlock() somewhere.
> 
> Thanks for pointing out about the finishBlock(). I will add finishBlock() at the end of PacketizeMI function. 
> 
> You probably know that we are getting the dependence information from the scheduler. Once we have the dependence info, along with the DFA resource manager, we can packetize the way our architecture prefers.  We are not using the scheduler to *schedule* instructions during packetization. Hence, we have enterRegion() and exitRegion() around schedule. Esssentially, this logic is borrowed from around line 200 of MachineScheduler.cpp

After callling ScheduleDAGInstrs::exitRegion, no one should refer DAG for that region (it happens to work, it's just a minor abuse). Likewise, after calling finishBlock no one should ask for the DAG's current block. I only mention this because others are learning the API from your client.

>> 
>> +  // Generate MI -> SU map.
>> +  //std::map <MachineInstr*, SUnit*> MIToSUnit;
>> +  MIToSUnit.clear();
>> +  for (unsigned i = 0, e = VLIWScheduler->SUnits.size(); i != e; ++i) {
>> +    SUnit *SU = &VLIWScheduler->SUnits[i];
>> +    MIToSUnit[SU->getInstr()] = SU;
>> +  }
>> 
>> I added ScheduleDAGInstrs::MISUnitMap so you wouldn't need your own. I haven't tested it with a PostRA scheduler, but           would like to know if it doesn't work.
> 
> Have you checked this functionality in? I don't see it.

ScheduleDAGInstrs::initSUnits populates the map. I'm not sure why that wouldn't work for you. Note that the ExitSU is not mapped, but you're not really using ExitSU anyway.

-Andy

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