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

[Ralf Jung via llvm-commits]

RalfJung wrote:

I just learned that saying "storing poison is UB" is also incoherent with the docs for dead_on_unwind, which say

> More precisely, the behavior is as-if any memory written through the pointer during the execution of the function is overwritten with a poison value on unwind.

So, closing in favor of https://github.com/llvm/llvm-project/issues/143527.

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