[PATCH] D103874: [IR] Rename the shufflevector's undef mask to poison

[Juneyoung Lee via Phabricator via cfe-commits]

aqjune added a comment.

PR31524 (https://github.com/llvm/llvm-project/issues/31524) discusses about the lowering of such intrinsics.
According to the PR, it seems users consider undefined intrinsics as returning unknown but consistent bits.

If it works, my updates in the draft (https://github.com/aqjune/llvm-project/commit/b4393e36b33ca08ce77ae662479ceaf9a76eab8b) will improve backends dealing with freeze(poison), which will help lowering `_mm256_cast*` with zero copy.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D103874/new/

https://reviews.llvm.org/D103874