[llvm-commits] [llvm] r132022 - /llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp

[Cameron Zwarich]

On 2011-05-25, at 1:45 AM, Cameron Zwarich wrote:

> On 2011-05-24, at 4:12 PM, Evan Cheng wrote:
> 
>> @@ -910,12 +916,27 @@
>>    // successor if they become single-entry, those PHI nodes may
>>    // be in the Users list.
>> 
>> +    BasicBlock *Switch = SI->getParent();
>> +    BasicBlock *SISucc = SI->getSuccessor(DeadCase);
>> +    BasicBlock *Latch = L->getLoopLatch();
>> +    // If the DeadCase successor dominates all of the predecessors of the
>> +    // loop latch, then the transformation isn't safe since it will delete
>> +    // the predecessor edges to the latch.
>> +    if (Latch) {
>> +      bool DominateAll = true;
>> +      for (pred_iterator PI = pred_begin(Latch), PE = pred_end(Latch);
>> +           DominateAll && PI != PE; ++PI)
>> +        if (!DT->dominates(SISucc, *PI))
>> +          DominateAll = false;
>> +      if (DominateAll)
>> +        continue;
>> +    }
> 
> You only need to check whether SISucc dominates Latch here. Also, you should be change this check

Oops. This should read "should be able to change this check".

Cameron