[PATCH] D89050: Add support for !noundef metatdata on loads

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert added subscribers: Tyker, spatel.
jdoerfert added a comment.

While this is certainly in line with the prior art, I would like to revisit the trade-offs of metadata on loads vs assume. While we need to make assume side-effect free (but potentially UB so we keep control dependences), it would allow us to reduce the number of encodings. Let's say you promote a load with `noundef`, you might introduce an "assume nodundef" for the promoted value anyway. That begs the question why not use assume anyway. (FWIW, when metadata was introduced for these things assume did not allow non-boolean properties.)

I'd be interested what others think :)


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https://reviews.llvm.org/D89050