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

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D93818#2804522 <https://reviews.llvm.org/D93818#2804522>, @aqjune wrote:

> Hi all,
>
> Before diving into further updates in InstCombine (D94380 <https://reviews.llvm.org/D94380> and D93817 <https://reviews.llvm.org/D93817>), what about pinning down this LangRef update first & letting people know via llvm-dev mail?

That sounds good to me. I'm not sure about the different pieces that are left. I know we already updated many, but not all, places in IR to use poison *vector operand* for shufflevector with the change to IRBuilder, so making things consistent for that seems like an obviously good step. Changing the shuffle *mask* has different concerns? If there is still regression potential, can you re-describe those (here or on llvm-dev)?

> The remaining updates at D94380 <https://reviews.llvm.org/D94380> and D93817 <https://reviews.llvm.org/D93817> are about non-syntactic changes; before them, many syntactic updates to make the placeholder `poison` have been done so far (D9381 <https://reviews.llvm.org/D9381> has links to such patches).

Lost a digit in that link (D9381 <https://reviews.llvm.org/D9381>?).


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https://reviews.llvm.org/D93818