[PATCH] D109537: [InstCombine] move extend after insertelement if both operands are extended

Fri Sep 10 05:27:48 PDT 2021

spatel added a comment.

In D109537#2994331 <https://reviews.llvm.org/D109537#2994331>, @spatel wrote:

> In D109537#2992713 <https://reviews.llvm.org/D109537#2992713>, @RKSimon wrote:
>
>> Should we handle trunc as well? https://alive2.llvm.org/ce/z/93QN9g
>
> I want to check that codegen isn't impacted by using insertelement on a wider (possible illegal type) vector op, but I think the answer is 'yes'.

We would need to deal with something like this in the backend to be safe:
https://godbolt.org/z/E1nKvd6e3

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https://reviews.llvm.org/D109537