[PATCH] D23432: [AliasSetTracker] Degrade AliasSetTracker results when may-alias sets get too large.

[Philip Reames via llvm-commits]

On 08/20/2016 12:38 PM, Hal Finkel wrote:
> hfinkel added a comment.
>
> In https://reviews.llvm.org/D23432#521624, @reames wrote:
>
>> I am not actively objecting to this patch, but I really don't like the overall direction here.  Having a threshold where our ability to optimize falls off a cliff just seems really undesirable.  As Hal pointed out, there are likely options for summarizing alias sets to allow quicker AA queries.  How much have we explored that design space?
>
> My understanding from the discussion is that all uses of the ASTracker are going to be replaced with MemorySSA-based algorithms; that is why I was okay with this (for now). If we still need an AST concept, then we'll want to do something more sophisticated.
I haven't been following the MemorySSA work recently.  Do we have a 
concrete near term date in mind for enabling MemorySSA?  If not, I am 
not okay with an attitude of "MemorySSA will fix everything... 
someday".  That's a very dangerous road to start walking down.
>