[LLVMdev] AliasSetTracker

[Chris Lattner]

On Aug 17, 2009, at 4:16 PM, Marcus Hicks wrote:

> I started using the AliasSetTracker, but I have a problem.

Hi Marcus,

At best, anders-aa is beta-quality.  It probably has several bugs and  
is not really ready to be widely used.

-Chris

>
> I am using -basicaa -anders-aa and optimizations are enabled for  
> llvm-gcc and llvm-ld.
> I use an instruction visitor to populate the alias set tracker, but  
> two pointers end up in different alias sets.
> While investigating this I notice at one point that if I call:
>
> bool New = false;
> AliasSet &X = AST->getAliasSetForPointer(Pointer, Size, &New);
>
> After this call, New is true
> but AST->containsPointer(Pointer, Size) is false! Shouldn't it be  
> true at this point?
>
> If I call again getAliasSetForPointer after resetting New, it  
> remains false, as I expect it after the first call.
>
> But AST->getAliasSetForPointerIfExists(Pointer, Size) returns null.  
> Again, shouldn't it return the same alias set as the first call?
>
> Am I misunderstanding something? This seems to work without  
> optimizations or without -anders-aa.
>
> Using revision 79271
>
> Best regards,
> Marcus
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