[PATCH] D15680: [Polly] Do not check JSON alignment of scalar accesses

[Tobias Grosser via llvm-commits]

On 01/15/2016 06:21 PM, Michael Kruse wrote:
> 2016-01-15 18:00 GMT+01:00 Tobias Grosser <tobias at grosser.es>:
>> On 01/15/2016 05:53 PM, Michael Kruse wrote:
>>>
>>> This revision was automatically updated to reflect the committed changes.
>>> Closed by commit rL257904: Do not check JSON alignment of scalar accesses
>>> (authored by Meinersbur).
>>>
>>> Changed prior to commit:
>>>     http://reviews.llvm.org/D15680?vs=43337&id=44998#toc
>>>
>>> Repository:
>>>     rL LLVM
>>>
>>> http://reviews.llvm.org/D15680
>>>
>>> Files:
>>>     polly/trunk/lib/Exchange/JSONExporter.cpp
>>>
>>> Index: polly/trunk/lib/Exchange/JSONExporter.cpp
>>> ===================================================================
>>> --- polly/trunk/lib/Exchange/JSONExporter.cpp
>>> +++ polly/trunk/lib/Exchange/JSONExporter.cpp
>>> @@ -304,33 +304,35 @@
>>>          isl_id *OutId = isl_map_get_tuple_id(currentAccessMap,
>>> isl_dim_out);
>>>          newAccessMap = isl_map_set_tuple_id(newAccessMap, isl_dim_out,
>>> OutId);
>>>
>>> -      // We keep the old alignment, thus we cannot allow accesses to
>>> memory
>>> -      // locations that were not accessed before if the alignment of the
>>> access
>>> -      // is not the default alignment.
>>> -      bool SpecialAlignment = true;
>>> -      if (LoadInst *LoadI =
>>> dyn_cast<LoadInst>(MA->getAccessInstruction())) {
>>> -        SpecialAlignment =
>>> -            DL.getABITypeAlignment(LoadI->getType()) !=
>>> LoadI->getAlignment();
>>> -      } else if (StoreInst *StoreI =
>>> -                     dyn_cast<StoreInst>(MA->getAccessInstruction())) {
>>> -        SpecialAlignment =
>>> -            DL.getABITypeAlignment(StoreI->getValueOperand()->getType())
>>> !=
>>> -            StoreI->getAlignment();
>>> -      }
>>> +      if (MA->isArrayKind()) {
>>
>>
>> An early 'continue' would help to keep the alignment low, e.g.,
>>
>> if (!MA->isArrayKind())
>>    continue();
>
> ... and break the code because there part behind the conditional in
> the same loop is not executed anymore for array kinds.
>
> Except you want to load only array kinds. In that case the the test
> should come a lot earlier in the code. But this is a change in
> behaviour I did not want to address.

Sorry, I missed that.

Best
Tobi