Re: [tree-ssa] alias analysis

[Diego Novillo <dnovillo at redhat dot com>]

On Tue, 11 Feb 2003, Jeff Law wrote:

> Your scheme depends on having every object which has the same alias set
> being represented by a single tag.  Then you just need to check things
> against that representative tag.
> 
Yes.

> In my scheme for separating loads and stores, we can have different
> tags for stores to addressable objects with the same underlying tag.
> 
> ie
> 
>   int x = 5;
>   int y = 10;
> 
>   foo (&x, &y);
> 
> 
> We'd have distinct tags for x & y, even though they have the same alias
> set.
> 
Now you lost me.  I thought you were separating load from store
aliases?  Aren't x and y store aliases here?  Or is it load
aliases?  I think I need a step-by-step description again :)


> This is important when we check aliased loads -- we have to look through
> *all* the tags rather than quitting when we find a alias.  The number of
> tags is proportional to the number of stores to unique addressable variables
> and the number of pointer stores using unique alias sets.
> 
Maybe we could add an attribute to each alias set to determine if
it's a load or a store alias?



Diego.