[llvm-commits] [llvm] r132805 - /llvm/trunk/lib/CodeGen/TailDuplication.cpp

[Bob Wilson]

On Jun 10, 2011, at 1:48 PM, Bob Wilson wrote:

> I'd really like to see a testcase for this, because I can't figure out how this could matter.
> 
> We explicitly rule out tail-duplication for single-block loops, i.e., when the tail block is its own successor.  You're checking here to exclude a PHI that uses a register defined in the same basic block, but wouldn't that always fail the single-block loop check?

Oh wait, I guess it could go through an intermediate block.  Nevermind.

> 
> On Jun 9, 2011, at 1:55 PM, Rafael Espindola wrote:
> 
>> Author: rafael
>> Date: Thu Jun  9 15:55:41 2011
>> New Revision: 132805
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=132805&view=rev
>> Log:
>> A PHI in this basic block is a use in another basic block.
>> 
>> Modified:
>>   llvm/trunk/lib/CodeGen/TailDuplication.cpp
>> 
>> Modified: llvm/trunk/lib/CodeGen/TailDuplication.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TailDuplication.cpp?rev=132805&r1=132804&r2=132805&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/TailDuplication.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/TailDuplication.cpp Thu Jun  9 15:55:41 2011
>> @@ -239,7 +239,7 @@
>>            MachineOperand &UseMO = UI.getOperand();
>>            MachineInstr *UseMI = &*UI;
>>            ++UI;
>> -            if (UseMI->getParent() == DefBB)
>> +            if (UseMI->getParent() == DefBB && !UseMI->isPHI())
>>              continue;
>>            SSAUpdate.RewriteUse(UseMO);
>>          }
>> 
>> 
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits