[PATCH] D153453: [MemCpyOpt] implement single BB stack-move optimization which unify the static unescaped allocas

[Vitaly Buka via Phabricator via llvm-commits]

vitalybuka added a comment.

However what I see is that:

- src has no lifetime markers - so it's considered alive all the time
- dst has lifetiem markers

I guess the pass removes dst and transfer lifetimes to src, effectively reducing scope. So I would recommend to handle this case some how.  In general dst lifetime can only expand src lifetime.

BTW. Also there are cases when lifetime is not very trivial between basic block. We don't have issue with that yet, but I think it's better to bail out and don't touch if we have more then 1 start/end for source or dst, or final lifetime can not be expressed as single range.


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https://reviews.llvm.org/D153453