[PATCH] D79053: [SVE] Fix invalid uses of VectorType::getNumElements() in ValueTracking

[Christopher Tetreault via Phabricator via llvm-commits]

ctetreau added a comment.

After spending some time considering how to deal with some breakages caused by my previous version of this patch, I've decided to change my approach.

For the most part, any function that uses a DemandedElts does not actually do the right thing for scalable vectors. An obvious bandaid that can be applied to this to do *something* is to just ignore the DemandedElts for scalable vectors and do some default behavior (such as considering the entire vector). However, I think this is dangerous because code may break if this function returns results for vector elements that the caller does not expect to get results for. Regardless, I would like to see a real fix be implemented rather than time being spent on applying many layers of band aids.


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  https://reviews.llvm.org/D79053/new/

https://reviews.llvm.org/D79053