[PATCH] D116942: GlobalISel: Fix legalization error where CSE leaves behind dead defs

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D116942#3231726 <https://reviews.llvm.org/D116942#3231726>, @Petar.Avramovic wrote:

> LGTM.
>
>> The G_UNMERGE_VALUES of the G_SEXT of the G_BUILD_VECTOR would introduce a G_SEXT for each of the scalars.
>
> Is there a reason why we don't have simpler pattern where `conversion opcode` of `merge like opcode` is not used by G_UNMERGE_VALUES (in this case only G_SEXT of the G_BUILD_VECTOR -> G_BUILD_VECTOR of G_SEXT for each of the scalars).

The ArtifactValueFinder should probably be tracking a stack of encountered conversion artifacts and replaying them with the new value types


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https://reviews.llvm.org/D116942