[llvm-dev] PartialAlias: different start addresses

[Nuno Lopes via llvm-dev]

Hi,

I going through the alias analysis documentation 
(http://llvm.org/docs/AliasAnalysis.html) and noticed the following in the 
definition of PartialAlias:
"
The PartialAlias response is used when the two memory objects are known to 
be overlapping in some way, but *do not start at the same address*.
"

Is it really required that the objects do no start at the same address?  if 
that's the case the AA algorithm would need to prove that.
I'm asking this because:
1) This condition seems very strict and I don't think it's met in a few 
places I found by manual inspection
2) I couldn't find any client that uses this information in a meaningful 
way. Is there a use case for PartialAlias w/ strict distinct starting 
addresses?

Thanks,
Nuno