[PATCH] D98112: [LangRef] mention that the lifetime intrinsics' description in LangRef isn't everything

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune added inline comments.


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Comment at: llvm/docs/LangRef.rst:18127
+the stack coloring algorithm cannot conclude that ``ptr`` is a stack-allocated
+object.
 
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RalfJung wrote:
> Would this alternatively be captured by saying that if ptr is a stack-allocated object, then it *might* have the effect of the original `alloca` creating a dead object and this intrinsic making it live (but non-deterministically, not doing this and just replacing the content by poison is also allowed)?
It will help remove the mentioning of dependency on stack coloring's implementation, but due to practical reasons I think the current text is better.

It's because the current text reveals the problem of the status quo: alloca's lifetime depends on the stack coloring's implementation.
I think this mentioning will help people in the future raise questions about removal of this dependency, if lucky enough. Since this isn't a small problem, fully resolving this would require a dedicated team... I don't know.

Also, personally I prefer being simple here; nondeterminism is a hard concept and there's an opportunity that it can be interpreted differently by readers.


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https://reviews.llvm.org/D98112