1 files changed, 38 insertions, 3 deletions

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index 6d1305393e1..e8443aeb715 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -3855,6 +3855,8 @@ bool llvm::UpgradeRetainReleaseMarker(Module &M) {
 }
 
 void llvm::UpgradeARCRuntimeCalls(Module &M) {
+  // This lambda converts normal function calls to ARC runtime functions to
+  // intrinsic calls.
   auto UpgradeToIntrinsic = [&](const char *OldFunc,
                                 llvm::Intrinsic::ID IntrinsicFunc) {
     Function *Fn = M.getFunction(OldFunc);
@@ -3863,11 +3865,44 @@ void llvm::UpgradeARCRuntimeCalls(Module &M) {
       return;
 
     Function *NewFn = llvm::Intrinsic::getDeclaration(&M, IntrinsicFunc);
-    Fn->replaceAllUsesWith(NewFn);
-    Fn->eraseFromParent();
+
+    for (auto I = Fn->user_begin(), E = Fn->user_end(); I != E;) {
+      CallInst *CI = dyn_cast<CallInst>(*I++);
+      if (!CI || CI->getCalledFunction() != Fn)
+        continue;
+
+      IRBuilder<> Builder(CI->getParent(), CI->getIterator());
+      FunctionType *NewFuncTy = NewFn->getFunctionType();
+      SmallVector<Value *, 2> Args;
+
+      for (unsigned I = 0, E = CI->getNumArgOperands(); I != E; ++I) {
+        Value *Arg = CI->getArgOperand(I);
+        // Bitcast argument to the parameter type of the new function if it's
+        // not a variadic argument.
+        if (I < NewFuncTy->getNumParams())
+          Arg = Builder.CreateBitCast(Arg, NewFuncTy->getParamType(I));
+        Args.push_back(Arg);
+      }
+
+      // Create a call instruction that calls the new function.
+      CallInst *NewCall = Builder.CreateCall(NewFuncTy, NewFn, Args);
+      NewCall->setTailCallKind(cast<CallInst>(CI)->getTailCallKind());
+      NewCall->setName(CI->getName());
+
+      // Bitcast the return value back to the type of the old call.
+      Value *NewRetVal = Builder.CreateBitCast(NewCall, CI->getType());
+
+      if (!CI->use_empty())
+        CI->replaceAllUsesWith(NewRetVal);
+      CI->eraseFromParent();
+    }
+
+    if (Fn->use_empty())
+      Fn->eraseFromParent();
   };
 
-  // Unconditionally convert "clang.arc.use" to "llvm.objc.clang.arc.use".
+  // Unconditionally convert a call to "clang.arc.use" to a call to
+  // "llvm.objc.clang.arc.use".
   UpgradeToIntrinsic("clang.arc.use", llvm::Intrinsic::objc_clang_arc_use);
 
   // Return if the bitcode doesn't have the arm64 retainAutoreleasedReturnValue