[PATCH] D93376: [LangRef] Clarify the semantics of lifetime intrinsics

[Nuno Lopes via Phabricator via llvm-commits]

nlopes added a comment.

A contradiction in the proposed semantics vs the comments in the code is that we state that subsequent lifetime.start don't change the address of the alloca. There's only one address per alloca, even if it may have multiple disjoint liveness ranges.
It would be good to get confirmation from some CodeGen folks that the implemented algorithm respects this condition and that there are no plans to make the algorithm more aggressive in a way that may break this assumption.
Having multiple start/end pairs for the same alloca is not common, so I think imposing this condition is fine. It gives us free movement of gep/ptr2int, which is a good tradeoff.


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https://reviews.llvm.org/D93376