[PATCH] D93793: [IR] Let IRBuilder's CreateVectorSplat use poison as inselt's placeholder

[Juneyoung Lee via Phabricator via cfe-commits]

aqjune added inline comments.


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Comment at: llvm/lib/IR/IRBuilder.cpp:1021
   Value *Zeros = ConstantAggregateZero::get(VectorType::get(I32Ty, EC));
   return CreateShuffleVector(V, Undef, Zeros, Name + ".splat");
 }
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nikic wrote:
> aqjune wrote:
> > nlopes wrote:
> > > while at it, don't you want to change this one to poison as well?
> > It would be great, but there are many other places that create shufflevector with undef args (InstCombineCalls, etc). Since this and related patches are big changes, I think it might be good to land these first.
> I think in this case it makes sense to change both at once, as it's part of one construction. It's odd that one uses undef and the other poison, even though both are equally non-demanded.
If the relevant patches are to be landed at once, I think the series of patches are being too big to maintain... :(
I'd like to make shufflevector's placeholder as poison in another iteration.


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  https://reviews.llvm.org/D93793/new/

https://reviews.llvm.org/D93793