[PATCH] D80437: [CodeGen] Let computeKnownBits do something sensible for scalable vectors

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

It's not clear how we actually want to represent DemandedElts for scalable vectors.  I think we'd go through all the callers before changing anything in that respect, so explicitly bailing out seems better than intentionally synthesizing something which might be wrong anyway.

For MaskedValueIsZero specifically, maybe makes sense to change the implementation to `return Mask.isSubsetOf(computeKnownBits(V, Depth).Zero);`, instead of trying to synthesize DemandedElts.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D80437/new/

https://reviews.llvm.org/D80437