[PATCH] Allow tail call optimization through multiple/nested struct extractions/insertions

[Evan Cheng]

On Apr 19, 2013, at 10:31 AM, Stephen Lin <swlin at post.harvard.edu> wrote:

>> This part confuses a bit:
>> 
>> +static bool sameNoopInput(const Value *V1, const Value *V2,
>> +                          SmallVectorImpl<unsigned> &Els1,
>> +                          SmallVectorImpl<unsigned> &Els2,
>> +                          const TargetLowering &TLI) {
>> +  using std::swap;
>> +  bool swapParity;
>> +  bool isSame = sameNoopInput(V1, V2, Els1, Els2, swapParity, TLI);
>> +  if (swapParity) {
>> +    // Revert to origin Els1 and Els2 to avoid confusing recursive calls
>> +    swap(V1, V2);
>> +    swap(Els1, Els2);
>> +  }
>> +  return isSame;
>> +}
>> 
>> Why is it necessary to swap V1 and V2? They are not passed by reference. Otherwise, I don't see any issue with the patch. Please update it and if LNT testing looks fine please commit the patch.
>> 
> 
> Oh, that's embarrassing :) I got rid of that and consolidated it back
> into one function.
> 
> Yes, LNT looks fine. Also, I don't have commit access, actually, so
> could you commit for me?

Please follow the instruction to request commit access first:
http://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access

You should commit it. Please do be on the look out for test failures. Like I said, the patch looks good but tail call can be tricky.

Evan

> 
> Thanks,
> Stephen
> <tail-call-nested-struct.patch>