Kill every call to @clang.arc.use in the ARC contract phase.

llvm-svn: 177769
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
index 1c13d1c..5d0865e 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
@@ -453,6 +453,10 @@
       if (isa<AllocaInst>(Inst))
         TailOkForStoreStrongs = false;
       continue;
+    case IC_IntrinsicUser:
+      // Remove calls to @clang.arc.use(...).
+      Inst->eraseFromParent();
+      continue;
     default:
       continue;
     }