Optimize isValueEqualInPotentialCycles

[• dberlin]

Summary

On larger test cases, we actually spend some time going to grab pass info and such, to be able to do the for loop, even if there is nothing in the visited set.

[hfinkel]

In the future, please post your patches with full context (instructions are: http://llvm.org/docs/Phabricator.html#requesting-a-review-via-the-web-interface)

LGTM.

[• dberlin]

Yes, apologies, arc diff was throwing errors on this for some reason, so i
did it manually.

lib/Analysis/BasicAliasAnalysis.cpp

   if (!Inst)
     return true;
 
+  if (VisitedPhiBBs.empty())
+    return true;
+
   if (VisitedPhiBBs.size() > MaxNumPhiBBsValueReachabilityCheck)
     return false;