[llvm] LangRef: storing poison in memory is UB (PR #141339)

[Ralf Jung via llvm-commits]

RalfJung wrote:

I don't like it either -- I just think if that's the reality right now, we should at least write it down. Currently there is no way for frontends to know that they are not supposed to put `poison` into memory; I was extremely surprised when I first heard about this.

I guess another way to frame this would be to file an issue saying that putting poison in memory can lead to surprising issues, and referencing this in the LangRef as a known issue without making it look like intended behavior? However, from what @nikic told me, this is apparently quite hard to fix.

https://github.com/llvm/llvm-project/pull/141339