llvm dev - Aug 2021 - Some questions about pointers analysis

Hi,1. Function PointerMayBeCaptured take an argument StoreCaptures. Some call
sites pass true to this argument(for example in LICM and AliasAnalysis). As far
as I understand,  PointerMayBeCaptured must always be conservative, therefore it
can't produce wrong results even if StoreCaptures is false.
Why StoreCaptures is not always false? In which cases it must be true?2. Alias
analyses contains getModRefInfo methods to retrieve function call sites ModRef
information, but I have not found any alias analysis, which actually use
pointers assignments and pointers modifications information and examine
load/store instructions of analyzed function. As far as I see, there are no
suitable alias analysis implemented, because no one alias analysis examine both
functions inside and pointers passed as arguments. It is not trivial to create
the data structure required for this analysis, because it has to check if an
modification of certain memory location exists in a function or in some other
function, that can be called from it, and the data structure should not take
more than near linear time in total to construction and responding to queries.
But with some loss of analyze precision, it can be implemented. Have there been
researches that have shown ineffectiveness of such analysis or it simply have
not been implemented?

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