[PATCH] D57653: GlobalISel: Combine g_extract with g_merge_values

[Amara Emerson via Phabricator via llvm-commits]

aemerson accepted this revision.
aemerson added a comment.
This revision is now accepted and ready to land.

It's not quite true that these combines are required for legalization, but to clean up instructions required to satisfy the type requirements. Operations left over should still be legalized in some way so as to not cause a selection failure later, even if the codegen is poor quality.

Anyway, this is something that was on my todo list anyway, the aarch64 test regression looks ok. We don't want a hasOneUse case because sometimes we can have multiple extracts which we definitely want to replace with copies if we can.


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https://reviews.llvm.org/D57653