[LLVMdev] tbaa

Daniel Berlin dberlin at dberlin.org
Mon Dec 5 21:39:22 PST 2011

On Mon, Dec 5, 2011 at 11:08 PM,  <liyi at cs.toronto.edu> wrote:
>> On Dec 5, 2011, at 6:04 PM, Daniel Berlin wrote:
>>> Yet, aa-eval still says otherwise.
>> The problem is with aa-eval. It collects all the pointer values in a
>> function, and then just makes a bunch of raw pointer queries, rather than
>> considering dereferences. TBAA tags are only attached to dereferences.
>> So TBAA always has to say MayAlias for every aa-eval query.
>> Dan
> Hi Dan,
> So do you know how to get the correct results from tbaa? It seems
> "print-alias-sets" also has all the pointers in one set.

If you want it to say that float * and int * don't alias, you will
have to enhance clang to generate TBAA tags for pointer types
It should already say that float * and int don't alias, and int * and
float don't alias.

You can see equivalent hand-written examples in

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