Index: llvm/trunk/lib/IR/AutoUpgrade.cpp
===================================================================
--- llvm/trunk/lib/IR/AutoUpgrade.cpp
+++ llvm/trunk/lib/IR/AutoUpgrade.cpp
@@ -493,6 +493,12 @@
 static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
   assert(F && "Illegal to upgrade a non-existent Function.");
 
+  // Upgrade intrinsics "clang.arc.use" which doesn't start with "llvm.".
+  if (F->getName() == "clang.arc.use") {
+    NewFn = nullptr;
+    return true;
+  }
+
   // Quickly eliminate it, if it's not a candidate.
   StringRef Name = F->getName();
   if (Name.size() <= 8 || !Name.startswith("llvm."))
@@ -1571,6 +1577,14 @@
     // Get the Function's name.
     StringRef Name = F->getName();
 
+    // clang.arc.use is an old name for llvm.arc.clang.arc.use. It is dropped
+    // from upgrader because the optimizer now only recognizes intrinsics for
+    // ARC runtime calls.
+    if (Name == "clang.arc.use") {
+      CI->eraseFromParent();
+      return;
+    }
+
     assert(Name.startswith("llvm.") && "Intrinsic doesn't start with 'llvm.'");
     Name = Name.substr(5);
 
Index: llvm/trunk/test/Bitcode/upgrade-clang-arc-use.ll
===================================================================
--- llvm/trunk/test/Bitcode/upgrade-clang-arc-use.ll
+++ llvm/trunk/test/Bitcode/upgrade-clang-arc-use.ll
@@ -0,0 +1,14 @@
+; Test upgrade of clang.arc.use by removing it.
+; Bitcode input generated from llvm 6.0
+
+; RUN: llvm-dis %s.bc -o - | FileCheck %s
+
+%0 = type opaque
+define void @foo() {
+  %1 = tail call %0* @foo0()
+; CHECK-NOT: clang.arc.use
+  call void (...) @clang.arc.use(%0* %1)
+  ret void
+}
+declare %0* @foo0()
+declare void @clang.arc.use(...)