[PATCH] D93818: [LangRef] Update shufflevector's semantics to return poison if the mask is undef

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

Using `undef` in the shuffle mask to indicate a `poison` result seems pretty confusing to me. I think we should use `poison` as the marker instead. We could allow both undef/poison in input IR, but at least the output IR rendering should use poison (the internal representation is something else anyway, as shuffle masks are no longer Values).


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https://reviews.llvm.org/D93818