[LLVMdev] Alias Analysis Problem in LICM

Gan george.gan at gmail.com
Mon Nov 7 22:17:57 PST 2011

> Yes.  The current TBAA implementation is conservative, with the idea that it
> can become more aggressive (and with TBAA, this fundamentally means
> "more dangerous") with incremental steps.


Could you disclose more details about how to implement the "incremental steps"
to handle more complicated alias cases? For example, differentiate
different pointers
that point to different types. and use this information to improve
alias analysis accuracy?

> It's interesting to note that clang's own source code is known to violate the TBAA
> rules for pointers (it's thought to be unlikely to cause trouble in practice).  There
> are reasons for caution in this area.

I don't get your point here. What "TBAA rules" are violated by
"clang's own source code"?
Where does this violation happen? and what caution we should have in this area?

Thanks for your reply!

Best Regards


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