[PATCH] D71620: [Attributor] AAValueConstantRange: Value range analysis using constant range

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert added inline comments.


================
Comment at: llvm/lib/Transforms/IPO/Attributor.cpp:4980
+    return getKnown().intersectWith(SCEVR).intersectWith(LVIR);
+  }
+
----------------
uenoku wrote:
> jdoerfert wrote:
> > Shouldn't we merge the SCEV and LVI information into the known state during intialization and then be done with it?
> I didn't merge the SCEV and LVI information into initialization because I want to utilize the position where the value is used(=`CtxI`).  I mean, 
> ```
> int abs(int u){
>   if(u>=0){
>     return u;
>   }
>   else 
>     return -u;
> }
> ```
> In this case, the argument `u` has a different known range in each uses.  
> Do you have a better way to handle these kinds of flow- and context-sensitive information?
We can do both, right? I mean you already call the SCEV in some initialize I think. Let's call both in all initializations with the `getCtxI()` context. If the context changes I'm fine with calling it again though.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71620/new/

https://reviews.llvm.org/D71620