Added debug message to ObjCARC when we transform an objc_autoreleaseR…

…eturnValue => objc_autorelease due to its operand not being used as a return value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171669 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/ObjCARC.cpp

@@ -2298,8 +2298,20 @@ ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV) {
 
   Changed = true;
   ++NumPeeps;
+
+  DEBUG(dbgs() << "ObjCARCOpt::OptimizeAutoreleaseRVCall: Transforming "
+                  "objc_autoreleaseReturnValue => "
+                  "objc_autorelease since its operand is not used as a return "
+                  "value.\n"
+                  "                                       Old: "
+               << *AutoreleaseRV << "\n");
+
   cast<CallInst>(AutoreleaseRV)->
     setCalledFunction(getAutoreleaseCallee(F.getParent()));
+
+  DEBUG(dbgs() << "                                       New: "
+               << *AutoreleaseRV << "\n");
+
 }
 
 /// OptimizeIndividualCalls - Visit each call, one at a time, and make