[llvm] r310495 - CFLAA: return MustAlias when pointers p, q are equal, i.e.,

[Nuno Lopes via llvm-commits]

> On Wed, Aug 9, 2017 at 10:02 AM, Nuno Lopes via llvm-commits wrote:
>> Author: nlopes
>> Date: Wed Aug  9 10:02:18 2017
>> New Revision: 310495
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=310495&view=rev
>> Log:
>> CFLAA: return MustAlias when pointers p, q are equal, i.e.,
>> must-alias(p, sz_p, p, sz_q)  irrespective of access sizes sz_p, sz_q
>>
>> As discussed a couple of weeks ago on the ML.
>> This makes the behavior consistent with that of BasicAA.
>> AA clients already check the obj size themselves and may not require the
>> obj size to match exactly the access size (e.g., in case of store 
>> forwarding)
>>
>
> Thanks.
> Can you add a testcase for this? (if it's not too hard).

I tried, but failed, sorry. It's not easy to trigger this code from the 
outside since if you have 2 memory operations over the same pointer all the 
opt passes that print AA information won't print anything since they skip 
alias check between pairs of the same Value.  Hence it's not easy to trigger 
(if at all).

Nuno