[PATCH] D73941: GlobalISel: Allow CSE of G_IMPLICIT_DEF

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle added a comment.

Could this pessimize code generation? If you have multiple G_IMPLICIT_DEFs, you can push them down close to their respective user and just have different undef register sources in each of those places.

With CSE'd G_IMPLICIT_DEF, they all end up using the same value, i.e. we potentially end up having to keep a register alive over a long interval.


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  https://reviews.llvm.org/D73941/new/

https://reviews.llvm.org/D73941