llvm dev - Sep 2019 - Finding "last uses" of an alloca in the function.

Hello, LLVMDev.

Given an alloca in the entry block, I want to find all its uses after which
it is used no more. I tried naive approach by recursively iterating over
uses(), but faced 2 problems:

1. I have to take into account "indirect" uses introduced by
stores/loads.
2. In case of loops the use chain I built become circular.

I came up with an idea by tracking current "use path", but wanted to
ask if
there is a LLVM analysis for this first.

Thanks in advance.
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Hi,

I think you can sort all basic blocks in SCC order by using SCCIterator. Then
you can get a total order of all alloca users.

Regards,
- Min
> On Sep 24, 2019, at 3:22 AM, Gleb Popov via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> Hello, LLVMDev.
> 
> Given an alloca in the entry block, I want to find all its uses after which
it is used no more. I tried naive approach by recursively iterating over uses(),
but faced 2 problems:
> 
> 1. I have to take into account "indirect" uses introduced by
stores/loads.
> 2. In case of loops the use chain I built become circular.
> 
> I came up with an idea by tracking current "use path", but wanted
to ask if there is a LLVM analysis for this first.
> 
> Thanks in advance.
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