[PATCH] D10368: Analyze recursive PHI nodes in BasicAA

[hfinkel at anl.gov]

hfinkel added a comment.

In http://reviews.llvm.org/D10368#201839, @tobiasvk_caf wrote:

> Sanjoy, thanks for clarifying the semantics of undef. I can see how my code would break if aliasGEP ever started to exploit those semantics. I have been thinking of what else could be used to represent "any arbitrary value that the compiler cannot reason about"... I suppose we could create another temporary, like a load from undef? Pushing logic to special-case those temporary GEP values directly into aliasGEP may be another option but it seems a little intrusive to me.


Ah, and on this point, please make sure you add comments in the code about this, both where the undef is created, but also in aliasGEP.


http://reviews.llvm.org/D10368