llvm dev - Aug 2009 - [LLVMdev] andersen's alias analysis

On Aug 26, 2009, at 6:40 PM, Max Stonebraker wrote:
> Hello,
>
> Does the LLVM Andersens alias analysis handle function pointers  
> precisely? I ran it and it looks like it says every function points  
> points to the universal set. Is this what I should expect?
Hi Max,

I don't know the answer offhand but please keep in mind that the  
current andersen's pass has many known problems and bugs.  Consider it  
"research quality".

-Chris

Thanks for the reply.

Would you happen to know whether there a global alias analysis written for
LLVM that is more robust? Is the Steensgaard pass any more reliable?

Max

On Thu, Aug 27, 2009 at 10:01 AM, Daniel Berlin <dberlin at dberlin.org>
wrote:
> At one point it handled function pointers.
> As chris says, it's buggy and probably broken.
> Some function pointers also do point to the universal set (like global
> function pointers).
>
>
> On Wed, Aug 26, 2009 at 10:11 PM, Chris Lattner<clattner at
apple.com> wrote:
> > On Aug 26, 2009, at 6:40 PM, Max Stonebraker wrote:
> >> Hello,
> >>
> >> Does the LLVM Andersens alias analysis handle function pointers
> >> precisely? I ran it and it looks like it says every function
points
> >> points to the universal set. Is this what I should expect?
> >
> > Hi Max,
> >
> > I don't know the answer offhand but please keep in mind that the
> > current andersen's pass has many known problems and bugs. 
Consider it
> > "research quality".
> >
> > -Chris
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
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On Aug 27, 2009, at 5:43 PM, Robert Zeh wrote:
> Might I suggest the following patch, because this issue has bite me  
> too?  You're lured in by the initial good results from the Andersens  
> alias analysis, only to discover the bugs later on.
Thanks, applied in r80328, along with a flag in the "opt -help" output
as well.

-Chris
>
> Robert Zeh
>
> On Aug 26, 2009, at 9:11 PM, Chris Lattner wrote:
>
>> On Aug 26, 2009, at 6:40 PM, Max Stonebraker wrote:
>>> Hello,
>>>
>>> Does the LLVM Andersens alias analysis handle function pointers
>>> precisely? I ran it and it looks like it says every function points
>>> points to the universal set. Is this what I should expect?
>>
>> Hi Max,
>>
>> I don't know the answer offhand but please keep in mind that the
>> current andersen's pass has many known problems and bugs.  Consider
>> it
>> "research quality".
>>
>> -Chris
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
> <anders-patch.txt>