[PATCH] D124722: [InstCombine] extract(u[add|sub].with.overflow(X, C), 0) --> [add|sub](X, C)

[Nikita Popov via Phabricator via llvm-commits]

nikic added a reviewer: spatel.
nikic added a comment.

Hrm, unfortunately canonicalizing the intrinsic to add/icmp is not safe with undef: https://alive2.llvm.org/ce/z/cgiQ_n We effectively introduce two uses of undef, which can each take a different value.

This might need to be addressed on the front-end side instead, by not emitting uadd/usub intrinsics in the first place.


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https://reviews.llvm.org/D124722