[llvm-commits] [llvm] r51950 - /llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp

[Evan Cheng]

Hi Owen,

While you are doing this and cleaning up liveintervals. Can you add  
helper function to liveinterval for creating copy intervals etc.?

Evan

On Jun 4, 2008, at 10:55 AM, Owen Anderson wrote:

>
> +
> +  // Renumber the instructions so that we can perform the index  
> computations
> +  // needed to create new live intervals.
> +  LI.computeNumbering();
> +
> +  // For copies that we inserted at the ends of predecessors, we  
> construct
> +  // live intervals.  This is pretty easy, since we know that the  
> destination
> +  // register cannot have be in live at that point previously.  We  
> just have
> +  // to make sure that, for registers that serve as inputs to more  
> than one
> +  // PHI, we don't create multiple overlapping live intervals.
> +  std::set<unsigned> RegHandled;
> +  for (SmallVector<std::pair<unsigned, MachineInstr*>, 4>::iterator  
> I =
> +       InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I !=  
> E; ++I) {
> +    if (!RegHandled.count(I->first)) {
> +      LiveInterval& Interval = LI.getOrCreateInterval(I->first);
> +      VNInfo* VN = Interval.getNextValue(
> +          LI.getInstructionIndex(I->second) +  
> LiveIntervals::InstrSlots::DEF,
> +                                         I->second,  
> LI.getVNInfoAllocator());
> +      VN->hasPHIKill = true;
> +      VN->kills.push_back(LI.getMBBEndIdx(I->second->getParent()));
> +      LiveRange LR(LI.getInstructionIndex(I->second) +
> +                      LiveIntervals::InstrSlots::DEF,
> +                   LI.getMBBEndIdx(I->second->getParent()) + 1, VN);
> +      Interval.addRange(LR);
> +
> +      RegHandled.insert(I->first);
> +    }
> +  }
> }
>
> /// InsertCopies - insert copies into MBB and all of its successors
>
>
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