Eliminate the VNInfo::hasPHIKill() flag.

The only real user of the flag was removeCopyByCommutingDef(), and it
has been switched to LiveIntervals::hasPHIKill().

All the code changed by this patch was only concerned with computing and
propagating the flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161255 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/LiveInterval.cpp

@@ -737,9 +737,7 @@ void LiveInterval::print(raw_ostream &OS) const {
       } else {
         OS << vni->def;
         if (vni->isPHIDef())
-          OS << "-phidef";
-        if (vni->hasPHIKill())
-          OS << "-phikill";
+          OS << "-phi";
       }
     }
   }