[ObjCARC Debug Message] - Added debug message when we zap a matching retain/autorelease pair in ObjCARCOpt::OptimizeReturns.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171678 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/ObjCARC.cpp

@@ -3753,6 +3753,9 @@ void ObjCARCOpt::OptimizeReturns(Function &F) {
           // If so, we can zap the retain and autorelease.
           Changed = true;
           ++NumRets;
+          DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Erasing: " << *Retain
+                       << "\n                             Erasing: "
+                       << *Autorelease << "\n");
           EraseInstruction(Retain);
           EraseInstruction(Autorelease);
         }