[llvm-commits] value range analysis based on scalar-evolutions

[Nick Lewycky]

Chris Lattner wrote:
> On Jun 1, 2008, at 8:54 PM, Nick Lewycky wrote:
>
>   
>> I've implemented an analysis pass that uses SCEV to determine value  
>> ranges of integer-typed registers.
>>
>> Currently it maintains a map of Value* to ConstantRange*, which is  
>> rather inelegant. I was thinking we could have one analysis which  
>> would do that and others that would update the central analysis.
>>
>> I also implemented an optz'n pass based on it, but it hardly  
>> optimized anything and as such is not included in this patch.
>>     
> Hey Nick,
>
> Are you still working on this?  It looks like a really interesting  
> approach.  As Dan says, it would be best if it were lazy (computing  
> ranges when queried instead of in runOnFunction), but otherwise it  
> would be nice to go in the tree.
>
>   
Yes, it's still in my pending queue. I'm on vacation and away from my 
desktop so I don't have committing powers, or a tree I can run llvm-test 
on. I'd be more than happy for anyone else to commit it. Either way, 
I'll make the changes in response to review once I return home.

Nick