[clang] ed4718e - [ObjC][ARC] Use operand bundle 'clang.arc.attachedcall' instead of

Akira Hatanaka via cfe-commits cfe-commits at lists.llvm.org
Fri Feb 12 09:52:19 PST 2021


Author: Akira Hatanaka
Date: 2021-02-12T09:51:57-08:00
New Revision: ed4718eccb12bd42214ca4fb17d196d49561c0c7

URL: https://github.com/llvm/llvm-project/commit/ed4718eccb12bd42214ca4fb17d196d49561c0c7
DIFF: https://github.com/llvm/llvm-project/commit/ed4718eccb12bd42214ca4fb17d196d49561c0c7.diff

LOG: [ObjC][ARC] Use operand bundle 'clang.arc.attachedcall' instead of
explicitly emitting retainRV or claimRV calls in the IR

Background:

This fixes a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.

https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue

What this patch does to fix the problem:

- The front-end adds operand bundle "clang.arc.attachedcall" to calls,
  which indicates the call is implicitly followed by a marker
  instruction and an implicit retainRV/claimRV call that consumes the
  call result. In addition, it emits a call to
  @llvm.objc.clang.arc.noop.use, which consumes the call result, to
  prevent the middle-end passes from changing the return type of the
  called function. This is currently done only when the target is arm64
  and the optimization level is higher than -O0.

- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
  with the operand bundle in the IR and removes the inserted calls after
  processing the function.

- ARC contract pass emits retainRV/claimRV calls after the call with the
  operand bundle. It doesn't remove the operand bundle on the call since
  the backend needs it to emit the marker instruction. The retainRV and
  claimRV calls are emitted late in the pipeline to prevent optimization
  passes from transforming the IR in a way that makes it harder for the
  ARC middle-end passes to figure out the def-use relationship between
  the call and the retainRV/claimRV calls (which is the cause of
  PR31925).

- The function inliner removes an autoreleaseRV call in the callee if
  nothing in the callee prevents it from being paired up with the
  retainRV/claimRV call in the caller. It then inserts a release call if
  claimRV is attached to the call since autoreleaseRV+claimRV is
  equivalent to a release. If it cannot find an autoreleaseRV call, it
  tries to transfer the operand bundle to a function call in the callee.
  This is important since the ARC optimizer can remove the autoreleaseRV
  returning the callee result, which makes it impossible to pair it up
  with the retainRV/claimRV call in the caller. If that fails, it simply
  emits a retain call in the IR if retainRV is attached to the call and
  does nothing if claimRV is attached to it.

- SCCP refrains from replacing the return value of a call with a
  constant value if the call has the operand bundle. This ensures the
  call always has at least one user (the call to
  @llvm.objc.clang.arc.noop.use).

- This patch also fixes a bug in replaceUsesOfNonProtoConstant where
  multiple operand bundles of the same kind were being added to a call.

Future work:

- Use the operand bundle on x86-64.

- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
  calls with the operand bundles.

rdar://71443534

Differential Revision: https://reviews.llvm.org/D92808

Added: 
    clang/test/CodeGenObjC/arc-rv-attr.m
    llvm/include/llvm/Analysis/ObjCARCUtil.h
    llvm/test/Transforms/Inline/inline-retainRV-call.ll
    llvm/test/Transforms/ObjCARC/contract-rv-attr.ll
    llvm/test/Transforms/SCCP/clang-arc-rv.ll

Modified: 
    clang/lib/CodeGen/CGObjC.cpp
    clang/lib/CodeGen/CodeGenFunction.h
    clang/lib/CodeGen/CodeGenModule.cpp
    clang/lib/CodeGen/CodeGenModule.h
    clang/test/CodeGenObjC/arc-unsafeclaim.m
    llvm/docs/LangRef.rst
    llvm/include/llvm/IR/InstrTypes.h
    llvm/include/llvm/IR/Intrinsics.td
    llvm/include/llvm/IR/LLVMContext.h
    llvm/lib/Analysis/ObjCARCInstKind.cpp
    llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    llvm/lib/IR/AutoUpgrade.cpp
    llvm/lib/IR/Instructions.cpp
    llvm/lib/IR/LLVMContext.cpp
    llvm/lib/IR/Verifier.cpp
    llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
    llvm/lib/Transforms/ObjCARC/ObjCARC.cpp
    llvm/lib/Transforms/ObjCARC/ObjCARC.h
    llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
    llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
    llvm/lib/Transforms/ObjCARC/PtrState.cpp
    llvm/lib/Transforms/ObjCARC/PtrState.h
    llvm/lib/Transforms/Scalar/SCCP.cpp
    llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
    llvm/lib/Transforms/Utils/InlineFunction.cpp
    llvm/test/Bitcode/operand-bundles-bc-analyzer.ll
    llvm/test/CodeGen/AArch64/call-rv-marker.ll
    llvm/test/Transforms/DeadArgElim/deadretval.ll
    llvm/test/Transforms/ObjCARC/contract-marker-funclet.ll
    llvm/test/Transforms/ObjCARC/contract.ll
    llvm/test/Transforms/ObjCARC/intrinsic-use.ll
    llvm/test/Transforms/ObjCARC/rv.ll
    llvm/test/Transforms/TailCallElim/deopt-bundle.ll
    llvm/test/Verifier/operand-bundles.ll

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 3f930c76fe0a..663666b6bf8b 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -23,6 +23,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/BinaryFormat/MachO.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/InlineAsm.h"
@@ -2078,6 +2079,15 @@ void CodeGenFunction::EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values) {
   EmitNounwindRuntimeCall(fn, values);
 }
 
+/// Emit a call to "clang.arc.noop.use", which consumes the result of a call
+/// that has operand bundle "clang.arc.attachedcall".
+void CodeGenFunction::EmitARCNoopIntrinsicUse(ArrayRef<llvm::Value *> values) {
+  llvm::Function *&fn = CGM.getObjCEntrypoints().clang_arc_noop_use;
+  if (!fn)
+    fn = CGM.getIntrinsic(llvm::Intrinsic::objc_clang_arc_noop_use);
+  EmitNounwindRuntimeCall(fn, values);
+}
+
 static void setARCRuntimeFunctionLinkage(CodeGenModule &CGM, llvm::Value *RTF) {
   if (auto *F = dyn_cast<llvm::Function>(RTF)) {
     // If the target runtime doesn't naturally support ARC, emit weak
@@ -2304,10 +2314,11 @@ static void emitAutoreleasedReturnValueMarker(CodeGenFunction &CGF) {
     // with this marker yet, so leave a breadcrumb for the ARC
     // optimizer to pick up.
     } else {
-      const char *markerKey = "clang.arc.retainAutoreleasedReturnValueMarker";
-      if (!CGF.CGM.getModule().getModuleFlag(markerKey)) {
+      const char *retainRVMarkerKey = llvm::objcarc::getRVMarkerModuleFlagStr();
+      if (!CGF.CGM.getModule().getModuleFlag(retainRVMarkerKey)) {
         auto *str = llvm::MDString::get(CGF.getLLVMContext(), assembly);
-        CGF.CGM.getModule().addModuleFlag(llvm::Module::Error, markerKey, str);
+        CGF.CGM.getModule().addModuleFlag(llvm::Module::Error,
+                                          retainRVMarkerKey, str);
       }
     }
   }
@@ -2317,6 +2328,47 @@ static void emitAutoreleasedReturnValueMarker(CodeGenFunction &CGF) {
     CGF.Builder.CreateCall(marker, None, CGF.getBundlesForFunclet(marker));
 }
 
+static llvm::Value *emitOptimizedARCReturnCall(llvm::Value *value,
+                                               bool IsRetainRV,
+                                               CodeGenFunction &CGF) {
+  emitAutoreleasedReturnValueMarker(CGF);
+
+  // Add operand bundle "clang.arc.attachedcall" to the call instead of emitting
+  // retainRV or claimRV calls in the IR. We currently do this only when the
+  // optimization level isn't -O0 since global-isel, which is currently run at
+  // -O0, doesn't know about the operand bundle.
+
+  // FIXME: Do this when the target isn't aarch64.
+  if (CGF.CGM.getCodeGenOpts().OptimizationLevel > 0 &&
+      CGF.CGM.getTarget().getTriple().isAArch64()) {
+    llvm::Value *bundleArgs[] = {llvm::ConstantInt::get(
+        CGF.Int64Ty,
+        llvm::objcarc::getAttachedCallOperandBundleEnum(IsRetainRV))};
+    llvm::OperandBundleDef OB("clang.arc.attachedcall", bundleArgs);
+    auto *oldCall = cast<llvm::CallBase>(value);
+    llvm::CallBase *newCall = llvm::CallBase::addOperandBundle(
+        oldCall, llvm::LLVMContext::OB_clang_arc_attachedcall, OB, oldCall);
+    newCall->copyMetadata(*oldCall);
+    oldCall->replaceAllUsesWith(newCall);
+    oldCall->eraseFromParent();
+    CGF.EmitARCNoopIntrinsicUse(newCall);
+    return newCall;
+  }
+
+  bool isNoTail =
+      CGF.CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail();
+  llvm::CallInst::TailCallKind tailKind =
+      isNoTail ? llvm::CallInst::TCK_NoTail : llvm::CallInst::TCK_None;
+  ObjCEntrypoints &EPs = CGF.CGM.getObjCEntrypoints();
+  llvm::Function *&EP = IsRetainRV
+                            ? EPs.objc_retainAutoreleasedReturnValue
+                            : EPs.objc_unsafeClaimAutoreleasedReturnValue;
+  llvm::Intrinsic::ID IID =
+      IsRetainRV ? llvm::Intrinsic::objc_retainAutoreleasedReturnValue
+                 : llvm::Intrinsic::objc_unsafeClaimAutoreleasedReturnValue;
+  return emitARCValueOperation(CGF, value, nullptr, EP, IID, tailKind);
+}
+
 /// Retain the given object which is the result of a function call.
 ///   call i8* \@objc_retainAutoreleasedReturnValue(i8* %value)
 ///
@@ -2324,15 +2376,7 @@ static void emitAutoreleasedReturnValueMarker(CodeGenFunction &CGF) {
 /// call with completely 
diff erent semantics.
 llvm::Value *
 CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
-  emitAutoreleasedReturnValueMarker(*this);
-  llvm::CallInst::TailCallKind tailKind =
-      CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail()
-          ? llvm::CallInst::TCK_NoTail
-          : llvm::CallInst::TCK_None;
-  return emitARCValueOperation(
-      *this, value, nullptr,
-      CGM.getObjCEntrypoints().objc_retainAutoreleasedReturnValue,
-      llvm::Intrinsic::objc_retainAutoreleasedReturnValue, tailKind);
+  return emitOptimizedARCReturnCall(value, true, *this);
 }
 
 /// Claim a possibly-autoreleased return value at +0.  This is only
@@ -2344,15 +2388,7 @@ CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
 ///   call i8* \@objc_unsafeClaimAutoreleasedReturnValue(i8* %value)
 llvm::Value *
 CodeGenFunction::EmitARCUnsafeClaimAutoreleasedReturnValue(llvm::Value *value) {
-  emitAutoreleasedReturnValueMarker(*this);
-  llvm::CallInst::TailCallKind tailKind =
-      CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail()
-          ? llvm::CallInst::TCK_NoTail
-          : llvm::CallInst::TCK_None;
-  return emitARCValueOperation(
-      *this, value, nullptr,
-      CGM.getObjCEntrypoints().objc_unsafeClaimAutoreleasedReturnValue,
-      llvm::Intrinsic::objc_unsafeClaimAutoreleasedReturnValue, tailKind);
+  return emitOptimizedARCReturnCall(value, false, *this);
 }
 
 /// Release the given object.

diff  --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 8eb7adbc8fcb..dd77d70c21f4 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -4202,6 +4202,8 @@ class CodeGenFunction : public CodeGenTypeCache {
 
   void EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values);
 
+  void EmitARCNoopIntrinsicUse(ArrayRef<llvm::Value *> values);
+
   static Destroyer destroyARCStrongImprecise;
   static Destroyer destroyARCStrongPrecise;
   static Destroyer destroyARCWeak;

diff  --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 1c28c50e60f5..6321f745593b 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4535,7 +4535,6 @@ static void replaceUsesOfNonProtoConstant(llvm::Constant *old,
 
   llvm::Type *newRetTy = newFn->getReturnType();
   SmallVector<llvm::Value*, 4> newArgs;
-  SmallVector<llvm::OperandBundleDef, 1> newBundles;
 
   for (llvm::Value::use_iterator ui = old->use_begin(), ue = old->use_end();
          ui != ue; ) {
@@ -4592,6 +4591,7 @@ static void replaceUsesOfNonProtoConstant(llvm::Constant *old,
     newArgs.append(callSite->arg_begin(), callSite->arg_begin() + argNo);
 
     // Copy over any operand bundles.
+    SmallVector<llvm::OperandBundleDef, 1> newBundles;
     callSite->getOperandBundlesAsDefs(newBundles);
 
     llvm::CallBase *newCall;

diff  --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 618e2f857b07..4ff7deb70636 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -210,6 +210,9 @@ struct ObjCEntrypoints {
 
   /// void clang.arc.use(...);
   llvm::Function *clang_arc_use;
+
+  /// void clang.arc.noop.use(...);
+  llvm::Function *clang_arc_noop_use;
 };
 
 /// This class records statistics on instrumentation based profiling.

diff  --git a/clang/test/CodeGenObjC/arc-rv-attr.m b/clang/test/CodeGenObjC/arc-rv-attr.m
new file mode 100644
index 000000000000..3b769de1443c
--- /dev/null
+++ b/clang/test/CodeGenObjC/arc-rv-attr.m
@@ -0,0 +1,177 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios9 -fobjc-runtime=ios-9.0 -fobjc-arc -O -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK
+
+ at class A;
+
+A *makeA(void);
+
+void test_assign() {
+  __unsafe_unretained id x;
+  x = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_assign()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A:.*]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_assign_assign() {
+  __unsafe_unretained id x, y;
+  x = y = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_assign_assign()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_strong_assign_assign() {
+  __strong id x;
+  __unsafe_unretained id y;
+  x = y = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_strong_assign_assign()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 0) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    [[OLD:%.*]] = load i8*, i8** [[X]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[OLD]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[X]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[T0]])
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_assign_strong_assign() {
+  __unsafe_unretained id x;
+  __strong id y;
+  x = y = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_assign_strong_assign()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 0) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    [[OLD:%.*]] = load i8*, i8** [[Y]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[OLD]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[Y]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[T0]])
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_init() {
+  __unsafe_unretained id x = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_init()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_init_assignment() {
+  __unsafe_unretained id x;
+  __unsafe_unretained id y = x = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_init_assignment()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_strong_init_assignment() {
+  __unsafe_unretained id x;
+  __strong id y = x = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_strong_init_assignment()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 0) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[Y]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[T0]])
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_init_strong_assignment() {
+  __strong id x;
+  __unsafe_unretained id y = x = makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_init_strong_assignment()
+// CHECK:         [[X:%.*]] = alloca i8*
+// CHECK:         [[Y:%.*]] = alloca i8*
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 0) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    [[T1:%.*]] = bitcast [[A]]* [[T0]] to i8*
+// CHECK-NEXT:    [[OLD:%.*]] = load i8*, i8** [[X]]
+// CHECK-NEXT:    store i8* [[T1]], i8** [[X]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[OLD]])
+// CHECK-NEXT:    store i8* [[T1]], i8** [[Y]]
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    [[T0:%.*]] = load i8*, i8** [[X]]
+// CHECK-NEXT:    call void @llvm.objc.release(i8* [[T0]])
+// CHECK-NEXT:    bitcast
+// CHECK-NEXT:    lifetime.end
+// CHECK-NEXT:    ret void
+
+void test_ignored() {
+  makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_ignored()
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    ret void
+
+void test_cast_to_void() {
+  (void) makeA();
+}
+// CHECK-LABEL: define{{.*}} void @test_cast_to_void()
+// CHECK:         [[T0:%.*]] = call [[A]]* @makeA() [ "clang.arc.attachedcall"(i64 1) ]
+// CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use({{.*}} [[T0]])
+// CHECK-NEXT:    ret void
+
+// This is always at the end of the module.
+
+// CHECK-OPTIMIZED: !llvm.module.flags = !{!0,
+// CHECK-OPTIMIZED: !0 = !{i32 1, !"clang.arc.retainAutoreleasedReturnValueMarker", !"mov{{.*}}marker for objc_retainAutoreleaseReturnValue"}

diff  --git a/clang/test/CodeGenObjC/arc-unsafeclaim.m b/clang/test/CodeGenObjC/arc-unsafeclaim.m
index 8f95d1edc96c..08ff8eca8da5 100644
--- a/clang/test/CodeGenObjC/arc-unsafeclaim.m
+++ b/clang/test/CodeGenObjC/arc-unsafeclaim.m
@@ -4,11 +4,10 @@
 //   Make sure it works on x86-32.
 // RUN: %clang_cc1 -triple i386-apple-darwin11 -fobjc-runtime=macosx-fragile-10.11 -fobjc-arc -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-UNOPTIMIZED -check-prefix=CHECK-MARKED -check-prefix=CALL
 
-//   Make sure it works on ARM.
+//   Make sure it works on ARM64.
 // RUN: %clang_cc1 -triple arm64-apple-ios9 -fobjc-runtime=ios-9.0 -fobjc-arc -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-UNOPTIMIZED -check-prefix=CHECK-MARKED -check-prefix=CALL
-// RUN: %clang_cc1 -triple arm64-apple-ios9 -fobjc-runtime=ios-9.0 -fobjc-arc -O -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-OPTIMIZED -check-prefix=CALL
 
-//   Make sure it works on ARM64.
+//   Make sure it works on ARM.
 // RUN: %clang_cc1 -triple armv7-apple-ios9 -fobjc-runtime=ios-9.0 -fobjc-arc -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-UNOPTIMIZED -check-prefix=CHECK-MARKED -check-prefix=CALL
 // RUN: %clang_cc1 -triple armv7-apple-ios9 -fobjc-runtime=ios-9.0 -fobjc-arc -O -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-OPTIMIZED -check-prefix=CALL
 

diff  --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 8a98f955f5c8..c73d73f6ec12 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -2325,6 +2325,19 @@ When lowered, any relocated value will be recorded in the corresponding
 :ref:`stackmap entry <statepoint-stackmap-format>`.  See the intrinsic description
 for further details.
 
+ObjC ARC Attached Call Operand Bundles
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A ``"clang.arc.attachedcall`` operand bundle on a call indicates the call is
+implicitly followed by a marker instruction and a call to an ObjC runtime
+function that uses the result of the call. If the argument passed to the operand
+bundle is 0, ``@objc_retainAutoreleasedReturnValue`` is called. If 1 is passed,
+``@objc_unsafeClaimAutoreleasedReturnValue`` is called. A call with this bundle
+implicitly uses its return value.
+
+The operand bundle is needed to ensure the call is immediately followed by the
+marker instruction or the ObjC runtime call in the final output.
+
 .. _moduleasm:
 
 Module-Level Inline Assembly

diff  --git a/llvm/include/llvm/Analysis/ObjCARCUtil.h b/llvm/include/llvm/Analysis/ObjCARCUtil.h
new file mode 100644
index 000000000000..9345c892ff39
--- /dev/null
+++ b/llvm/include/llvm/Analysis/ObjCARCUtil.h
@@ -0,0 +1,50 @@
+//===- ObjCARCUtil.h - ObjC ARC Utility Functions ---------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file defines ARC utility functions which are used by various parts of
+/// the compiler.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_ANALYSIS_OBJCARCUTIL_H
+#define LLVM_LIB_ANALYSIS_OBJCARCUTIL_H
+
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/LLVMContext.h"
+
+namespace llvm {
+namespace objcarc {
+
+static inline const char *getRVMarkerModuleFlagStr() {
+  return "clang.arc.retainAutoreleasedReturnValueMarker";
+}
+
+enum AttachedCallOperandBundle : unsigned { RVOB_Retain, RVOB_Claim };
+
+static AttachedCallOperandBundle
+getAttachedCallOperandBundleEnum(bool IsRetain) {
+  return IsRetain ? RVOB_Retain : RVOB_Claim;
+}
+
+static inline bool hasAttachedCallOpBundle(const CallBase *CB, bool IsRetain) {
+  auto B = CB->getOperandBundle(LLVMContext::OB_clang_arc_attachedcall);
+  if (!B.hasValue())
+    return false;
+  return cast<ConstantInt>(B->Inputs[0])->getZExtValue() ==
+         getAttachedCallOperandBundleEnum(IsRetain);
+}
+
+static inline bool hasAttachedCallOpBundle(const CallBase *CB) {
+  return CB->getOperandBundle(LLVMContext::OB_clang_arc_attachedcall)
+      .hasValue();
+}
+
+} // end namespace objcarc
+} // end namespace llvm
+
+#endif

diff  --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
index f42ef48de6b3..c4963f668827 100644
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1214,6 +1214,15 @@ class CallBase : public Instruction {
   static CallBase *Create(CallBase *CB, ArrayRef<OperandBundleDef> Bundles,
                           Instruction *InsertPt = nullptr);
 
+  /// Create a clone of \p CB with operand bundle \p OB added.
+  static CallBase *addOperandBundle(CallBase *CB, uint32_t ID,
+                                    OperandBundleDef OB,
+                                    Instruction *InsertPt = nullptr);
+
+  /// Create a clone of \p CB with operand bundle \p ID removed.
+  static CallBase *removeOperandBundle(CallBase *CB, uint32_t ID,
+                                       Instruction *InsertPt = nullptr);
+
   static bool classof(const Instruction *I) {
     return I->getOpcode() == Instruction::Call ||
            I->getOpcode() == Instruction::Invoke ||

diff  --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index 58f0f86cae63..69a5701d5a8d 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -446,6 +446,9 @@ def int_objc_storeWeak                      : Intrinsic<[llvm_ptr_ty],
                                                          llvm_ptr_ty]>;
 def int_objc_clang_arc_use                  : Intrinsic<[],
                                                         [llvm_vararg_ty]>;
+def int_objc_clang_arc_noop_use : DefaultAttrsIntrinsic<[],
+                                                        [llvm_vararg_ty],
+                                                        [IntrInaccessibleMemOnly]>;
 def int_objc_unsafeClaimAutoreleasedReturnValue : Intrinsic<[llvm_ptr_ty],
                                                             [llvm_ptr_ty]>;
 def int_objc_retainedObject                 : Intrinsic<[llvm_ptr_ty],

diff  --git a/llvm/include/llvm/IR/LLVMContext.h b/llvm/include/llvm/IR/LLVMContext.h
index 8f8a35d07c64..1195a9e5fb28 100644
--- a/llvm/include/llvm/IR/LLVMContext.h
+++ b/llvm/include/llvm/IR/LLVMContext.h
@@ -87,12 +87,13 @@ class LLVMContext {
   /// operand bundle tags without comparing strings. Keep this in sync with
   /// LLVMContext::LLVMContext().
   enum : unsigned {
-    OB_deopt = 0,         // "deopt"
-    OB_funclet = 1,       // "funclet"
-    OB_gc_transition = 2, // "gc-transition"
-    OB_cfguardtarget = 3, // "cfguardtarget"
-    OB_preallocated = 4,  // "preallocated"
-    OB_gc_live = 5,       // "gc-live"
+    OB_deopt = 0,                  // "deopt"
+    OB_funclet = 1,                // "funclet"
+    OB_gc_transition = 2,          // "gc-transition"
+    OB_cfguardtarget = 3,          // "cfguardtarget"
+    OB_preallocated = 4,           // "preallocated"
+    OB_gc_live = 5,                // "gc-live"
+    OB_clang_arc_attachedcall = 6, // "clang.arc.attachedcall"
   };
 
   /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.

diff  --git a/llvm/lib/Analysis/ObjCARCInstKind.cpp b/llvm/lib/Analysis/ObjCARCInstKind.cpp
index 951907804227..704d15f3280d 100644
--- a/llvm/lib/Analysis/ObjCARCInstKind.cpp
+++ b/llvm/lib/Analysis/ObjCARCInstKind.cpp
@@ -140,6 +140,7 @@ ARCInstKind llvm::objcarc::GetFunctionClass(const Function *F) {
     return ARCInstKind::User;
   case Intrinsic::objc_sync_exit:
     return ARCInstKind::User;
+  case Intrinsic::objc_clang_arc_noop_use:
   case Intrinsic::objc_arc_annotation_topdown_bbstart:
   case Intrinsic::objc_arc_annotation_topdown_bbend:
   case Intrinsic::objc_arc_annotation_bottomup_bbstart:

diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index ea7d64bf94d4..dbf43fc97290 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2783,11 +2783,11 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
 
   // Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
   // have to do anything here to lower funclet bundles.
-  assert(!I.hasOperandBundlesOtherThan({LLVMContext::OB_deopt,
-                                        LLVMContext::OB_gc_transition,
-                                        LLVMContext::OB_gc_live,
-                                        LLVMContext::OB_funclet,
-                                        LLVMContext::OB_cfguardtarget}) &&
+  assert(!I.hasOperandBundlesOtherThan(
+             {LLVMContext::OB_deopt, LLVMContext::OB_gc_transition,
+              LLVMContext::OB_gc_live, LLVMContext::OB_funclet,
+              LLVMContext::OB_cfguardtarget,
+              LLVMContext::OB_clang_arc_attachedcall}) &&
          "Cannot lower invokes with arbitrary operand bundles yet!");
 
   const Value *Callee(I.getCalledOperand());
@@ -7876,7 +7876,8 @@ void SelectionDAGBuilder::visitCall(const CallInst &I) {
   // CFGuardTarget bundles are lowered in LowerCallTo.
   assert(!I.hasOperandBundlesOtherThan(
              {LLVMContext::OB_deopt, LLVMContext::OB_funclet,
-              LLVMContext::OB_cfguardtarget, LLVMContext::OB_preallocated}) &&
+              LLVMContext::OB_cfguardtarget, LLVMContext::OB_preallocated,
+              LLVMContext::OB_clang_arc_attachedcall}) &&
          "Cannot lower calls with arbitrary operand bundles!");
 
   SDValue Callee = getValue(I.getCalledOperand());

diff  --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index 23e7af6287b6..3134f7b15103 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -14,14 +14,15 @@
 
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Instruction.h"
 #include "llvm/IR/InstVisitor.h"
+#include "llvm/IR/Instruction.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsAArch64.h"
@@ -3996,7 +3997,7 @@ bool llvm::UpgradeDebugInfo(Module &M) {
 /// returns true if module is modified.
 static bool UpgradeRetainReleaseMarker(Module &M) {
   bool Changed = false;
-  const char *MarkerKey = "clang.arc.retainAutoreleasedReturnValueMarker";
+  const char *MarkerKey = objcarc::getRVMarkerModuleFlagStr();
   NamedMDNode *ModRetainReleaseMarker = M.getNamedMetadata(MarkerKey);
   if (ModRetainReleaseMarker) {
     MDNode *Op = ModRetainReleaseMarker->getOperand(0);

diff  --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index d6b4a4f5030f..b73528d89752 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -424,6 +424,35 @@ CallBase::BundleOpInfo &CallBase::getBundleOpInfoForOperand(unsigned OpIdx) {
   return *Current;
 }
 
+CallBase *CallBase::addOperandBundle(CallBase *CB, uint32_t ID,
+                                     OperandBundleDef OB,
+                                     Instruction *InsertPt) {
+  if (CB->getOperandBundle(ID))
+    return CB;
+
+  SmallVector<OperandBundleDef, 1> Bundles;
+  CB->getOperandBundlesAsDefs(Bundles);
+  Bundles.push_back(OB);
+  return Create(CB, Bundles, InsertPt);
+}
+
+CallBase *CallBase::removeOperandBundle(CallBase *CB, uint32_t ID,
+                                        Instruction *InsertPt) {
+  SmallVector<OperandBundleDef, 1> Bundles;
+  bool CreateNew = false;
+
+  for (unsigned I = 0, E = CB->getNumOperandBundles(); I != E; ++I) {
+    auto Bundle = CB->getOperandBundleAt(I);
+    if (Bundle.getTagID() == ID) {
+      CreateNew = true;
+      continue;
+    }
+    Bundles.emplace_back(Bundle);
+  }
+
+  return CreateNew ? Create(CB, Bundles, InsertPt) : CB;
+}
+
 //===----------------------------------------------------------------------===//
 //                        CallInst Implementation
 //===----------------------------------------------------------------------===//

diff  --git a/llvm/lib/IR/LLVMContext.cpp b/llvm/lib/IR/LLVMContext.cpp
index 4f292101256d..280db8c9bb6d 100644
--- a/llvm/lib/IR/LLVMContext.cpp
+++ b/llvm/lib/IR/LLVMContext.cpp
@@ -78,6 +78,12 @@ LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
          "gc-transition operand bundle id drifted!");
   (void)GCLiveEntry;
 
+  auto *ClangAttachedCall =
+      pImpl->getOrInsertBundleTag("clang.arc.attachedcall");
+  assert(ClangAttachedCall->second == LLVMContext::OB_clang_arc_attachedcall &&
+         "clang.arc.attachedcall operand bundle id drifted!");
+  (void)ClangAttachedCall;
+
   SyncScope::ID SingleThreadSSID =
       pImpl->getOrInsertSyncScopeID("singlethread");
   assert(SingleThreadSSID == SyncScope::SingleThread &&

diff  --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 6dd299ee9845..62ec09561bd8 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -3187,7 +3187,8 @@ void Verifier::visitCallBase(CallBase &Call) {
   // and at most one "preallocated" operand bundle.
   bool FoundDeoptBundle = false, FoundFuncletBundle = false,
        FoundGCTransitionBundle = false, FoundCFGuardTargetBundle = false,
-       FoundPreallocatedBundle = false, FoundGCLiveBundle = false;;
+       FoundPreallocatedBundle = false, FoundGCLiveBundle = false,
+       FoundAttachedCallBundle = false;
   for (unsigned i = 0, e = Call.getNumOperandBundles(); i < e; ++i) {
     OperandBundleUse BU = Call.getOperandBundleAt(i);
     uint32_t Tag = BU.getTagID();
@@ -3228,9 +3229,19 @@ void Verifier::visitCallBase(CallBase &Call) {
       Assert(!FoundGCLiveBundle, "Multiple gc-live operand bundles",
              Call);
       FoundGCLiveBundle = true;
+    } else if (Tag == LLVMContext::OB_clang_arc_attachedcall) {
+      Assert(!FoundAttachedCallBundle,
+             "Multiple \"clang.arc.attachedcall\" operand bundles", Call);
+      FoundAttachedCallBundle = true;
     }
   }
 
+  if (FoundAttachedCallBundle)
+    Assert(FTy->getReturnType()->isPointerTy(),
+           "a call with operand bundle \"clang.arc.attachedcall\" must call a "
+           "function returning a pointer",
+           Call);
+
   // Verify that each inlinable callsite of a debug-info-bearing function in a
   // debug-info-bearing function has a debug location attached to it. Failure to
   // do so causes assertion failures when the inliner sets up inline scope info.

diff  --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index c87478afe65c..dd91d31422c6 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -29,6 +29,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/Analysis/VectorUtils.h"
 #include "llvm/CodeGen/CallingConvLower.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -5653,11 +5654,12 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
   }
 
   unsigned CallOpc = AArch64ISD::CALL;
-  // Calls marked with "rv_marker" are special. They should be expanded to the
-  // call, directly followed by a special marker sequence. Use the CALL_RVMARKER
-  // to do that.
-  if (CLI.CB && CLI.CB->hasRetAttr("rv_marker")) {
-    assert(!IsTailCall && "tail calls cannot be marked with rv_marker");
+  // Calls with operand bundle "clang.arc.attachedcall" are special. They should
+  // be expanded to the call, directly followed by a special marker sequence.
+  // Use the CALL_RVMARKER to do that.
+  if (CLI.CB && objcarc::hasAttachedCallOpBundle(CLI.CB)) {
+    assert(!IsTailCall &&
+           "tail calls cannot be marked with clang.arc.attachedcall");
     CallOpc = AArch64ISD::CALL_RVMARKER;
   }
 

diff  --git a/llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h b/llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
index 258dc9240815..764dc5f92707 100644
--- a/llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
+++ b/llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
@@ -42,6 +42,7 @@ enum class ARCRuntimeEntryPointKind {
   Autorelease,
   StoreStrong,
   RetainRV,
+  ClaimRV,
   RetainAutorelease,
   RetainAutoreleaseRV,
 };
@@ -61,6 +62,7 @@ class ARCRuntimeEntryPoints {
     Autorelease = nullptr;
     StoreStrong = nullptr;
     RetainRV = nullptr;
+    ClaimRV = nullptr;
     RetainAutorelease = nullptr;
     RetainAutoreleaseRV = nullptr;
   }
@@ -85,6 +87,9 @@ class ARCRuntimeEntryPoints {
     case ARCRuntimeEntryPointKind::RetainRV:
       return getIntrinsicEntryPoint(RetainRV,
                                 Intrinsic::objc_retainAutoreleasedReturnValue);
+    case ARCRuntimeEntryPointKind::ClaimRV:
+      return getIntrinsicEntryPoint(
+          ClaimRV, Intrinsic::objc_unsafeClaimAutoreleasedReturnValue);
     case ARCRuntimeEntryPointKind::RetainAutorelease:
       return getIntrinsicEntryPoint(RetainAutorelease,
                                     Intrinsic::objc_retainAutorelease);
@@ -121,6 +126,9 @@ class ARCRuntimeEntryPoints {
   /// Declaration for objc_retainAutoreleasedReturnValue().
   Function *RetainRV = nullptr;
 
+  /// Declaration for objc_unsafeClaimAutoreleasedReturnValue().
+  Function *ClaimRV = nullptr;
+
   /// Declaration for objc_retainAutorelease().
   Function *RetainAutorelease = nullptr;
 

diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARC.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARC.cpp
index 970136392fdd..06b12149f597 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARC.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARC.cpp
@@ -14,7 +14,12 @@
 
 #include "ObjCARC.h"
 #include "llvm-c/Initialization.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/Instructions.h"
 #include "llvm/InitializePasses.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 
 namespace llvm {
   class PassRegistry;
@@ -37,3 +42,91 @@ void llvm::initializeObjCARCOpts(PassRegistry &Registry) {
 void LLVMInitializeObjCARCOpts(LLVMPassRegistryRef R) {
   initializeObjCARCOpts(*unwrap(R));
 }
+
+CallInst *objcarc::createCallInstWithColors(
+    FunctionCallee Func, ArrayRef<Value *> Args, const Twine &NameStr,
+    Instruction *InsertBefore,
+    const DenseMap<BasicBlock *, ColorVector> &BlockColors) {
+  FunctionType *FTy = Func.getFunctionType();
+  Value *Callee = Func.getCallee();
+  SmallVector<OperandBundleDef, 1> OpBundles;
+
+  if (!BlockColors.empty()) {
+    const ColorVector &CV = BlockColors.find(InsertBefore->getParent())->second;
+    assert(CV.size() == 1 && "non-unique color for block!");
+    Instruction *EHPad = CV.front()->getFirstNonPHI();
+    if (EHPad->isEHPad())
+      OpBundles.emplace_back("funclet", EHPad);
+  }
+
+  return CallInst::Create(FTy, Callee, Args, OpBundles, NameStr, InsertBefore);
+}
+
+std::pair<bool, bool>
+BundledRetainClaimRVs::insertAfterInvokes(Function &F, DominatorTree *DT) {
+  bool Changed = false, CFGChanged = false;
+
+  for (BasicBlock &BB : F) {
+    auto *I = dyn_cast<InvokeInst>(BB.getTerminator());
+
+    if (!I)
+      continue;
+
+    if (!objcarc::hasAttachedCallOpBundle(I))
+      continue;
+
+    BasicBlock *DestBB = I->getNormalDest();
+
+    if (!DestBB->getSinglePredecessor()) {
+      assert(I->getSuccessor(0) == DestBB &&
+             "the normal dest is expected to be the first successor");
+      DestBB = SplitCriticalEdge(I, 0, CriticalEdgeSplittingOptions(DT));
+      CFGChanged = true;
+    }
+
+    // We don't have to call insertRVCallWithColors since DestBB is the normal
+    // destination of the invoke.
+    insertRVCall(&*DestBB->getFirstInsertionPt(), I);
+    Changed = true;
+  }
+
+  return std::make_pair(Changed, CFGChanged);
+}
+
+CallInst *BundledRetainClaimRVs::insertRVCall(Instruction *InsertPt,
+                                              CallBase *AnnotatedCall) {
+  DenseMap<BasicBlock *, ColorVector> BlockColors;
+  return insertRVCallWithColors(InsertPt, AnnotatedCall, BlockColors);
+}
+
+CallInst *BundledRetainClaimRVs::insertRVCallWithColors(
+    Instruction *InsertPt, CallBase *AnnotatedCall,
+    const DenseMap<BasicBlock *, ColorVector> &BlockColors) {
+  IRBuilder<> Builder(InsertPt);
+  bool IsRetainRV = objcarc::hasAttachedCallOpBundle(AnnotatedCall, true);
+  Function *Func = EP.get(IsRetainRV ? ARCRuntimeEntryPointKind::RetainRV
+                                     : ARCRuntimeEntryPointKind::ClaimRV);
+  Type *ParamTy = Func->getArg(0)->getType();
+  Value *CallArg = Builder.CreateBitCast(AnnotatedCall, ParamTy);
+  auto *Call =
+      createCallInstWithColors(Func, CallArg, "", InsertPt, BlockColors);
+  RVCalls[Call] = AnnotatedCall;
+  return Call;
+}
+
+BundledRetainClaimRVs::~BundledRetainClaimRVs() {
+  if (ContractPass) {
+    // At this point, we know that the annotated calls can't be tail calls as
+    // they are followed by marker instructions and retainRV/claimRV calls. Mark
+    // them as notail, so that the backend knows these calls can't be tail
+    // calls.
+    for (auto P : RVCalls)
+      if (auto *CI = dyn_cast<CallInst>(P.second))
+        CI->setTailCallKind(CallInst::TCK_NoTail);
+  } else {
+    for (auto P : RVCalls)
+      EraseInstruction(P.first);
+  }
+
+  RVCalls.clear();
+}

diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARC.h b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
index 8227a8c6f75f..1f9d76969bfd 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARC.h
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
@@ -22,7 +22,10 @@
 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H
 #define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H
 
+#include "ARCRuntimeEntryPoints.h"
+#include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/Transforms/Utils/Local.h"
 
 namespace llvm {
@@ -87,6 +90,75 @@ void getEquivalentPHIs(PHINodeTy &PN, VectorTy &PHIList) {
   }
 }
 
+static inline MDString *getRVInstMarker(Module &M) {
+  const char *MarkerKey = getRVMarkerModuleFlagStr();
+  return dyn_cast_or_null<MDString>(M.getModuleFlag(MarkerKey));
+}
+
+/// Create a call instruction with the correct funclet token. This should be
+/// called instead of calling CallInst::Create directly unless the call is
+/// going to be removed from the IR before WinEHPrepare.
+CallInst *createCallInstWithColors(
+    FunctionCallee Func, ArrayRef<Value *> Args, const Twine &NameStr,
+    Instruction *InsertBefore,
+    const DenseMap<BasicBlock *, ColorVector> &BlockColors);
+
+class BundledRetainClaimRVs {
+public:
+  BundledRetainClaimRVs(ARCRuntimeEntryPoints &P, bool ContractPass)
+      : EP(P), ContractPass(ContractPass) {}
+  ~BundledRetainClaimRVs();
+
+  /// Insert a retainRV/claimRV call to the normal destination blocks of invokes
+  /// with operand bundle "clang.arc.attachedcall". If the edge to the normal
+  /// destination block is a critical edge, split it.
+  std::pair<bool, bool> insertAfterInvokes(Function &F, DominatorTree *DT);
+
+  /// Insert a retainRV/claimRV call.
+  CallInst *insertRVCall(Instruction *InsertPt, CallBase *AnnotatedCall);
+
+  /// Insert a retainRV/claimRV call with colors.
+  CallInst *insertRVCallWithColors(
+      Instruction *InsertPt, CallBase *AnnotatedCall,
+      const DenseMap<BasicBlock *, ColorVector> &BlockColors);
+
+  /// See if an instruction is a bundled retainRV/claimRV call.
+  bool contains(const Instruction *I) const {
+    if (auto *CI = dyn_cast<CallInst>(I))
+      return RVCalls.count(CI);
+    return false;
+  }
+
+  /// Remove a retainRV/claimRV call entirely.
+  void eraseInst(CallInst *CI) {
+    auto It = RVCalls.find(CI);
+    if (It != RVCalls.end()) {
+      // Remove call to @llvm.objc.clang.arc.noop.use.
+      for (auto U = It->second->user_begin(), E = It->second->user_end(); U != E; ++U)
+        if (auto *CI = dyn_cast<CallInst>(*U))
+          if (CI->getIntrinsicID() == Intrinsic::objc_clang_arc_noop_use) {
+            CI->eraseFromParent();
+            break;
+          }
+
+      auto *NewCall = CallBase::removeOperandBundle(
+          It->second, LLVMContext::OB_clang_arc_attachedcall, It->second);
+      NewCall->copyMetadata(*It->second);
+      It->second->replaceAllUsesWith(NewCall);
+      It->second->eraseFromParent();
+      RVCalls.erase(It);
+    }
+    EraseInstruction(CI);
+  }
+
+private:
+  /// A map of inserted retainRV/claimRV calls to annotated calls/invokes.
+  DenseMap<CallInst *, CallBase *> RVCalls;
+
+  ARCRuntimeEntryPoints &EP;
+  bool ContractPass;
+};
+
 } // end namespace objcarc
 } // end namespace llvm
 

diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
index 86d161116e8c..62161b5b6b40 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
@@ -32,6 +32,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/EHPersonalities.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/InstIterator.h"
@@ -63,13 +64,12 @@ namespace {
 
 class ObjCARCContract {
   bool Changed;
+  bool CFGChanged;
   AAResults *AA;
   DominatorTree *DT;
   ProvenanceAnalysis PA;
   ARCRuntimeEntryPoints EP;
-
-  /// A flag indicating whether this optimization pass should run.
-  bool Run;
+  BundledRetainClaimRVs *BundledInsts = nullptr;
 
   /// The inline asm string to insert between calls and RetainRV calls to make
   /// the optimization work on targets which need it.
@@ -98,6 +98,7 @@ class ObjCARCContract {
 public:
   bool init(Module &M);
   bool run(Function &F, AAResults *AA, DominatorTree *DT);
+  bool hasCFGChanged() const { return CFGChanged; }
 };
 
 class ObjCARCContractLegacyPass : public FunctionPass {
@@ -304,32 +305,6 @@ findRetainForStoreStrongContraction(Value *New, StoreInst *Store,
   return Retain;
 }
 
-/// Create a call instruction with the correct funclet token. Should be used
-/// instead of calling CallInst::Create directly.
-static CallInst *
-createCallInst(FunctionType *FTy, Value *Func, ArrayRef<Value *> Args,
-               const Twine &NameStr, Instruction *InsertBefore,
-               const DenseMap<BasicBlock *, ColorVector> &BlockColors) {
-  SmallVector<OperandBundleDef, 1> OpBundles;
-  if (!BlockColors.empty()) {
-    const ColorVector &CV = BlockColors.find(InsertBefore->getParent())->second;
-    assert(CV.size() == 1 && "non-unique color for block!");
-    Instruction *EHPad = CV.front()->getFirstNonPHI();
-    if (EHPad->isEHPad())
-      OpBundles.emplace_back("funclet", EHPad);
-  }
-
-  return CallInst::Create(FTy, Func, Args, OpBundles, NameStr, InsertBefore);
-}
-
-static CallInst *
-createCallInst(FunctionCallee Func, ArrayRef<Value *> Args, const Twine &NameStr,
-               Instruction *InsertBefore,
-               const DenseMap<BasicBlock *, ColorVector> &BlockColors) {
-  return createCallInst(Func.getFunctionType(), Func.getCallee(), Args, NameStr,
-                        InsertBefore, BlockColors);
-}
-
 /// Attempt to merge an objc_release with a store, load, and objc_retain to form
 /// an objc_storeStrong. An objc_storeStrong:
 ///
@@ -411,7 +386,8 @@ void ObjCARCContract::tryToContractReleaseIntoStoreStrong(
   if (Args[1]->getType() != I8X)
     Args[1] = new BitCastInst(Args[1], I8X, "", Store);
   Function *Decl = EP.get(ARCRuntimeEntryPointKind::StoreStrong);
-  CallInst *StoreStrong = createCallInst(Decl, Args, "", Store, BlockColors);
+  CallInst *StoreStrong =
+      objcarc::createCallInstWithColors(Decl, Args, "", Store, BlockColors);
   StoreStrong->setDoesNotThrow();
   StoreStrong->setDebugLoc(Store->getDebugLoc());
 
@@ -456,9 +432,14 @@ bool ObjCARCContract::tryToPeepholeInstruction(
   case ARCInstKind::RetainRV:
   case ARCInstKind::ClaimRV: {
     // If we're compiling for a target which needs a special inline-asm
-    // marker to do the return value optimization, insert it now.
+    // marker to do the return value optimization and the retainRV/claimRV call
+    // wasn't bundled with a call, insert the marker now.
     if (!RVInstMarker)
       return false;
+
+    if (BundledInsts->contains(Inst))
+      return false;
+
     BasicBlock::iterator BBI = Inst->getIterator();
     BasicBlock *InstParent = Inst->getParent();
 
@@ -486,7 +467,7 @@ bool ObjCARCContract::tryToPeepholeInstruction(
                          RVInstMarker->getString(),
                          /*Constraints=*/"", /*hasSideEffects=*/true);
 
-      createCallInst(IA, None, "", Inst, BlockColors);
+      objcarc::createCallInstWithColors(IA, None, "", Inst, BlockColors);
     }
   decline_rv_optimization:
     return false;
@@ -525,6 +506,12 @@ bool ObjCARCContract::tryToPeepholeInstruction(
     Inst->eraseFromParent();
     return true;
   default:
+    if (auto *CI = dyn_cast<CallInst>(Inst))
+      if (CI->getIntrinsicID() == Intrinsic::objc_clang_arc_noop_use) {
+        // Remove calls to @llvm.objc.clang.arc.noop.use(...).
+        Changed = true;
+        CI->eraseFromParent();
+      }
     return true;
   }
 }
@@ -534,16 +521,10 @@ bool ObjCARCContract::tryToPeepholeInstruction(
 //===----------------------------------------------------------------------===//
 
 bool ObjCARCContract::init(Module &M) {
-  // If nothing in the Module uses ARC, don't do anything.
-  Run = ModuleHasARC(M);
-  if (!Run)
-    return false;
-
   EP.init(&M);
 
   // Initialize RVInstMarker.
-  const char *MarkerKey = "clang.arc.retainAutoreleasedReturnValueMarker";
-  RVInstMarker = dyn_cast_or_null<MDString>(M.getModuleFlag(MarkerKey));
+  RVInstMarker = getRVInstMarker(M);
 
   return false;
 }
@@ -552,14 +533,16 @@ bool ObjCARCContract::run(Function &F, AAResults *A, DominatorTree *D) {
   if (!EnableARCOpts)
     return false;
 
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!Run)
-    return false;
-
-  Changed = false;
+  Changed = CFGChanged = false;
   AA = A;
   DT = D;
   PA.setAA(A);
+  BundledRetainClaimRVs BRV(EP, true);
+  BundledInsts = &BRV;
+
+  std::pair<bool, bool> R = BundledInsts->insertAfterInvokes(F, DT);
+  Changed |= R.first;
+  CFGChanged |= R.second;
 
   DenseMap<BasicBlock *, ColorVector> BlockColors;
   if (F.hasPersonalityFn() &&
@@ -584,6 +567,13 @@ bool ObjCARCContract::run(Function &F, AAResults *A, DominatorTree *D) {
 
     LLVM_DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
 
+    if (auto *CI = dyn_cast<CallInst>(Inst))
+      if (objcarc::hasAttachedCallOpBundle(CI)) {
+        BundledInsts->insertRVCallWithColors(&*I, CI, BlockColors);
+        --I;
+        Changed = true;
+      }
+
     // First try to peephole Inst. If there is nothing further we can do in
     // terms of undoing objc-arc-expand, process the next inst.
     if (tryToPeepholeInstruction(F, Inst, I, TailOkForStoreStrongs,
@@ -733,7 +723,6 @@ INITIALIZE_PASS_END(ObjCARCContractLegacyPass, "objc-arc-contract",
 void ObjCARCContractLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<AAResultsWrapperPass>();
   AU.addRequired<DominatorTreeWrapperPass>();
-  AU.setPreservesCFG();
 }
 
 Pass *llvm::createObjCARCContractPass() {
@@ -757,9 +746,11 @@ PreservedAnalyses ObjCARCContractPass::run(Function &F,
 
   bool Changed = OCAC.run(F, &AM.getResult<AAManager>(F),
                           &AM.getResult<DominatorTreeAnalysis>(F));
+  bool CFGChanged = OCAC.hasCFGChanged();
   if (Changed) {
     PreservedAnalyses PA;
-    PA.preserveSet<CFGAnalyses>();
+    if (!CFGChanged)
+      PA.preserveSet<CFGAnalyses>();
     return PA;
   }
   return PreservedAnalyses::all();

diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 1c447499519c..091ea143d6a2 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -41,6 +41,7 @@
 #include "llvm/Analysis/ObjCARCAliasAnalysis.h"
 #include "llvm/Analysis/ObjCARCAnalysisUtils.h"
 #include "llvm/Analysis/ObjCARCInstKind.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Constant.h"
@@ -483,6 +484,7 @@ namespace {
   /// The main ARC optimization pass.
 class ObjCARCOpt {
   bool Changed;
+  bool CFGChanged;
   ProvenanceAnalysis PA;
 
   /// A cache of references to runtime entry point constants.
@@ -492,8 +494,7 @@ class ObjCARCOpt {
   /// MDKind identifiers.
   ARCMDKindCache MDKindCache;
 
-  /// A flag indicating whether this optimization pass should run.
-  bool Run;
+  BundledRetainClaimRVs *BundledInsts = nullptr;
 
   /// A flag indicating whether the optimization that removes or moves
   /// retain/release pairs should be performed.
@@ -573,6 +574,7 @@ class ObjCARCOpt {
     void init(Module &M);
     bool run(Function &F, AAResults &AA);
     void releaseMemory();
+    bool hasCFGChanged() const { return CFGChanged; }
 };
 
 /// The main ARC optimization pass.
@@ -610,8 +612,6 @@ Pass *llvm::createObjCARCOptPass() { return new ObjCARCOptLegacyPass(); }
 void ObjCARCOptLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<ObjCARCAAWrapperPass>();
   AU.addRequired<AAResultsWrapperPass>();
-  // ARC optimization doesn't currently split critical edges.
-  AU.setPreservesCFG();
 }
 
 /// Turn objc_retainAutoreleasedReturnValue into objc_retain if the operand is
@@ -640,6 +640,9 @@ ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) {
     }
   }
 
+  assert(!BundledInsts->contains(RetainRV) &&
+         "a bundled retainRV's argument should be a call");
+
   // Turn it to a plain objc_retain.
   Changed = true;
   ++NumPeeps;
@@ -661,6 +664,9 @@ bool ObjCARCOpt::OptimizeInlinedAutoreleaseRVCall(
     Function &F, DenseMap<BasicBlock *, ColorVector> &BlockColors,
     Instruction *Inst, const Value *&Arg, ARCInstKind Class,
     Instruction *AutoreleaseRV, const Value *&AutoreleaseRVArg) {
+  if (BundledInsts->contains(Inst))
+    return false;
+
   // Must be in the same basic block.
   assert(Inst->getParent() == AutoreleaseRV->getParent());
 
@@ -844,6 +850,12 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) {
   for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
     Instruction *Inst = &*I++;
 
+    if (auto *CI = dyn_cast<CallInst>(Inst))
+      if (objcarc::hasAttachedCallOpBundle(CI)) {
+        BundledInsts->insertRVCall(&*I, CI);
+        Changed = true;
+      }
+
     ARCInstKind Class = GetBasicARCInstKind(Inst);
 
     // Skip this loop if this instruction isn't itself an ARC intrinsic.
@@ -922,6 +934,11 @@ void ObjCARCOpt::OptimizeIndividualCallImpl(
   // We can delete this call if it takes an inert value.
   SmallPtrSet<Value *, 1> VisitedPhis;
 
+  if (BundledInsts->contains(Inst)) {
+    UsedInThisFunction |= 1 << unsigned(Class);
+    return;
+  }
+
   if (IsNoopOnGlobal(Class))
     if (isInertARCValue(Inst->getOperand(0), VisitedPhis)) {
       if (!Inst->getType()->isVoidTy())
@@ -1542,7 +1559,7 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst,
     if (Ptr == Arg)
       continue; // Handled above.
     TopDownPtrState &S = MI->second;
-    if (S.HandlePotentialAlterRefCount(Inst, Ptr, PA, Class))
+    if (S.HandlePotentialAlterRefCount(Inst, Ptr, PA, Class, *BundledInsts))
       continue;
 
     S.HandlePotentialUse(Inst, Ptr, PA, Class);
@@ -2343,7 +2360,7 @@ void ObjCARCOpt::OptimizeReturns(Function &F) {
     ++NumRets;
     LLVM_DEBUG(dbgs() << "Erasing: " << *Retain << "\nErasing: " << *Autorelease
                       << "\n");
-    EraseInstruction(Retain);
+    BundledInsts->eraseInst(Retain);
     EraseInstruction(Autorelease);
   }
 }
@@ -2376,11 +2393,6 @@ void ObjCARCOpt::init(Module &M) {
   if (!EnableARCOpts)
     return;
 
-  // If nothing in the Module uses ARC, don't do anything.
-  Run = ModuleHasARC(M);
-  if (!Run)
-    return;
-
   // Intuitively, objc_retain and others are nocapture, however in practice
   // they are not, because they return their argument value. And objc_release
   // calls finalizers which can have arbitrary side effects.
@@ -2394,16 +2406,18 @@ bool ObjCARCOpt::run(Function &F, AAResults &AA) {
   if (!EnableARCOpts)
     return false;
 
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!Run)
-    return false;
-
-  Changed = false;
+  Changed = CFGChanged = false;
+  BundledRetainClaimRVs BRV(EP, false);
+  BundledInsts = &BRV;
 
   LLVM_DEBUG(dbgs() << "<<< ObjCARCOpt: Visiting Function: " << F.getName()
                     << " >>>"
                        "\n");
 
+  std::pair<bool, bool> R = BundledInsts->insertAfterInvokes(F, nullptr);
+  Changed |= R.first;
+  CFGChanged |= R.second;
+
   PA.setAA(&AA);
 
 #ifndef NDEBUG
@@ -2468,9 +2482,11 @@ PreservedAnalyses ObjCARCOptPass::run(Function &F,
   OCAO.init(*F.getParent());
 
   bool Changed = OCAO.run(F, AM.getResult<AAManager>(F));
+  bool CFGChanged = OCAO.hasCFGChanged();
   if (Changed) {
     PreservedAnalyses PA;
-    PA.preserveSet<CFGAnalyses>();
+    if (!CFGChanged)
+      PA.preserveSet<CFGAnalyses>();
     return PA;
   }
   return PreservedAnalyses::all();

diff  --git a/llvm/lib/Transforms/ObjCARC/PtrState.cpp b/llvm/lib/Transforms/ObjCARC/PtrState.cpp
index 6071ec3e4d91..89937b201400 100644
--- a/llvm/lib/Transforms/ObjCARC/PtrState.cpp
+++ b/llvm/lib/Transforms/ObjCARC/PtrState.cpp
@@ -11,6 +11,7 @@
 #include "ObjCARC.h"
 #include "llvm/Analysis/ObjCARCAnalysisUtils.h"
 #include "llvm/Analysis/ObjCARCInstKind.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
@@ -280,6 +281,13 @@ void BottomUpPtrState::HandlePotentialUse(BasicBlock *BB, Instruction *Inst,
       InsertAfter = skipDebugIntrinsics(InsertAfter);
 
     InsertReverseInsertPt(&*InsertAfter);
+
+    // Don't insert anything between a call/invoke with operand bundle
+    // "clang.arc.attachedcall" and the retainRV/claimRV call that uses the call
+    // result.
+    if (auto *CB = dyn_cast<CallBase>(Inst))
+      if (objcarc::hasAttachedCallOpBundle(CB))
+        SetCFGHazardAfflicted(true);
   };
 
   // Check for possible direct uses.
@@ -377,10 +385,9 @@ bool TopDownPtrState::MatchWithRelease(ARCMDKindCache &Cache,
   llvm_unreachable("Sequence unknown enum value");
 }
 
-bool TopDownPtrState::HandlePotentialAlterRefCount(Instruction *Inst,
-                                                   const Value *Ptr,
-                                                   ProvenanceAnalysis &PA,
-                                                   ARCInstKind Class) {
+bool TopDownPtrState::HandlePotentialAlterRefCount(
+    Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA,
+    ARCInstKind Class, const BundledRetainClaimRVs &BundledRVs) {
   // Check for possible releases. Treat clang.arc.use as a releasing instruction
   // to prevent sinking a retain past it.
   if (!CanDecrementRefCount(Inst, Ptr, PA, Class) &&
@@ -396,6 +403,12 @@ bool TopDownPtrState::HandlePotentialAlterRefCount(Instruction *Inst,
     assert(!HasReverseInsertPts());
     InsertReverseInsertPt(Inst);
 
+    // Don't insert anything between a call/invoke with operand bundle
+    // "clang.arc.attachedcall" and the retainRV/claimRV call that uses the call
+    // result.
+    if (BundledRVs.contains(Inst))
+      SetCFGHazardAfflicted(true);
+
     // One call can't cause a transition from S_Retain to S_CanRelease
     // and S_CanRelease to S_Use. If we've made the first transition,
     // we're done.

diff  --git a/llvm/lib/Transforms/ObjCARC/PtrState.h b/llvm/lib/Transforms/ObjCARC/PtrState.h
index 66614c06cb79..f143120ad6a4 100644
--- a/llvm/lib/Transforms/ObjCARC/PtrState.h
+++ b/llvm/lib/Transforms/ObjCARC/PtrState.h
@@ -31,6 +31,7 @@ class Value;
 namespace objcarc {
 
 class ARCMDKindCache;
+class BundledRetainClaimRVs;
 class ProvenanceAnalysis;
 
 /// \enum Sequence
@@ -202,7 +203,8 @@ struct TopDownPtrState : PtrState {
                           ProvenanceAnalysis &PA, ARCInstKind Class);
 
   bool HandlePotentialAlterRefCount(Instruction *Inst, const Value *Ptr,
-                                    ProvenanceAnalysis &PA, ARCInstKind Class);
+                                    ProvenanceAnalysis &PA, ARCInstKind Class,
+                                    const BundledRetainClaimRVs &BundledRVs);
 };
 
 } // end namespace objcarc

diff  --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index de6be52adf21..045abefd4741 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -144,9 +144,8 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
   /// represented here for efficient lookup.
   SmallPtrSet<Function *, 16> MRVFunctionsTracked;
 
-  /// MustTailFunctions - Each function here is a callee of non-removable
-  /// musttail call site.
-  SmallPtrSet<Function *, 16> MustTailCallees;
+  /// A list of functions whose return cannot be modified.
+  SmallPtrSet<Function *, 16> MustPreserveReturnsInFunctions;
 
   /// TrackingIncomingArguments - This is the set of functions for whose
   /// arguments we make optimistic assumptions about and try to prove as
@@ -238,16 +237,14 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
       TrackedRetVals.insert(std::make_pair(F, ValueLatticeElement()));
   }
 
-  /// AddMustTailCallee - If the SCCP solver finds that this function is called
-  /// from non-removable musttail call site.
-  void AddMustTailCallee(Function *F) {
-    MustTailCallees.insert(F);
+  /// Add function to the list of functions whose return cannot be modified.
+  void addToMustPreserveReturnsInFunctions(Function *F) {
+    MustPreserveReturnsInFunctions.insert(F);
   }
 
-  /// Returns true if the given function is called from non-removable musttail
-  /// call site.
-  bool isMustTailCallee(Function *F) {
-    return MustTailCallees.count(F);
+  /// Returns true if the return of the given function cannot be modified.
+  bool mustPreserveReturn(Function *F) {
+    return MustPreserveReturnsInFunctions.count(F);
   }
 
   void AddArgumentTrackedFunction(Function *F) {
@@ -319,12 +316,6 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
     return MRVFunctionsTracked;
   }
 
-  /// getMustTailCallees - Get the set of functions which are called
-  /// from non-removable musttail call sites.
-  const SmallPtrSet<Function *, 16> getMustTailCallees() {
-    return MustTailCallees;
-  }
-
   /// markOverdefined - Mark the specified value overdefined.  This
   /// works with both scalars and structs.
   void markOverdefined(Value *V) {
@@ -1650,16 +1641,19 @@ static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
   assert(Const && "Constant is nullptr here!");
 
   // Replacing `musttail` instructions with constant breaks `musttail` invariant
-  // unless the call itself can be removed
-  CallInst *CI = dyn_cast<CallInst>(V);
-  if (CI && CI->isMustTailCall() && !CI->isSafeToRemove()) {
-    Function *F = CI->getCalledFunction();
+  // unless the call itself can be removed.
+  // Calls with "clang.arc.attachedcall" implicitly use the return value and
+  // those uses cannot be updated with a constant.
+  CallBase *CB = dyn_cast<CallBase>(V);
+  if (CB && ((CB->isMustTailCall() && !CB->isSafeToRemove()) ||
+             CB->getOperandBundle(LLVMContext::OB_clang_arc_attachedcall))) {
+    Function *F = CB->getCalledFunction();
 
     // Don't zap returns of the callee
     if (F)
-      Solver.AddMustTailCallee(F);
+      Solver.addToMustPreserveReturnsInFunctions(F);
 
-    LLVM_DEBUG(dbgs() << "  Can\'t treat the result of musttail call : " << *CI
+    LLVM_DEBUG(dbgs() << "  Can\'t treat the result of call " << *CB
                       << " as a constant\n");
     return false;
   }
@@ -1821,11 +1815,12 @@ static void findReturnsToZap(Function &F,
   if (!Solver.isArgumentTrackedFunction(&F))
     return;
 
-  // There is a non-removable musttail call site of this function. Zapping
-  // returns is not allowed.
-  if (Solver.isMustTailCallee(&F)) {
-    LLVM_DEBUG(dbgs() << "Can't zap returns of the function : " << F.getName()
-                      << " due to present musttail call of it\n");
+  if (Solver.mustPreserveReturn(&F)) {
+    LLVM_DEBUG(
+        dbgs()
+        << "Can't zap returns of the function : " << F.getName()
+        << " due to present musttail or \"clang.arc.attachedcall\" call of "
+           "it\n");
     return;
   }
 

diff  --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 9e7cccc88412..8cc649a8c1ed 100644
--- a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -247,7 +247,10 @@ static bool markTails(Function &F, bool &AllCallsAreTailCalls,
           isa<PseudoProbeInst>(&I))
         continue;
 
-      bool IsNoTail = CI->isNoTailCall() || CI->hasOperandBundles();
+      // Special-case operand bundle "clang.arc.attachedcall".
+      bool IsNoTail =
+          CI->isNoTailCall() || CI->hasOperandBundlesOtherThan(
+                                    LLVMContext::OB_clang_arc_attachedcall);
 
       if (!IsNoTail && CI->doesNotAccessMemory()) {
         // A call to a readnone function whose arguments are all things computed

diff  --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 3026342cc4a6..5f75ead1247b 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -27,8 +27,9 @@
 #include "llvm/Analysis/CaptureTracking.h"
 #include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/Analysis/ProfileSummaryInfo.h"
-#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/Analysis/VectorUtils.h"
 #include "llvm/IR/Argument.h"
@@ -61,6 +62,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
 #include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
 #include <algorithm>
 #include <cassert>
@@ -1650,6 +1652,99 @@ void llvm::updateProfileCallee(
   }
 }
 
+/// An operand bundle "clang.arc.attachedcall" on a call indicates the call
+/// result is implicitly consumed by a call to retainRV or claimRV immediately
+/// after the call. This function inlines the retainRV/claimRV calls.
+///
+/// There are three cases to consider:
+///
+/// 1. If there is a call to autoreleaseRV that takes a pointer to the returned
+///    object in the callee return block, the autoreleaseRV call and the
+///    retainRV/claimRV call in the caller cancel out. If the call in the caller
+///    is a claimRV call, a call to objc_release is emitted.
+///
+/// 2. If there is a call in the callee return block that doesn't have operand
+///    bundle "clang.arc.attachedcall", the operand bundle on the original call
+///    is transferred to the call in the callee.
+///
+/// 3. Otherwise, a call to objc_retain is inserted if the call in the caller is
+///    a retainRV call.
+static void
+inlineRetainOrClaimRVCalls(CallBase &CB,
+                           const SmallVectorImpl<ReturnInst *> &Returns) {
+  Module *Mod = CB.getModule();
+  bool IsRetainRV = objcarc::hasAttachedCallOpBundle(&CB, true),
+       IsClaimRV = !IsRetainRV;
+
+  for (auto *RI : Returns) {
+    Value *RetOpnd = objcarc::GetRCIdentityRoot(RI->getOperand(0));
+    BasicBlock::reverse_iterator I = ++(RI->getIterator().getReverse());
+    BasicBlock::reverse_iterator EI = RI->getParent()->rend();
+    bool InsertRetainCall = IsRetainRV;
+    IRBuilder<> Builder(RI->getContext());
+
+    // Walk backwards through the basic block looking for either a matching
+    // autoreleaseRV call or an unannotated call.
+    for (; I != EI;) {
+      auto CurI = I++;
+
+      // Ignore casts.
+      if (isa<CastInst>(*CurI))
+        continue;
+
+      if (auto *II = dyn_cast<IntrinsicInst>(&*CurI)) {
+        if (II->getIntrinsicID() == Intrinsic::objc_autoreleaseReturnValue &&
+            II->hasNUses(0) &&
+            objcarc::GetRCIdentityRoot(II->getOperand(0)) == RetOpnd) {
+          // If we've found a matching authoreleaseRV call:
+          // - If claimRV is attached to the call, insert a call to objc_release
+          //   and erase the autoreleaseRV call.
+          // - If retainRV is attached to the call, just erase the autoreleaseRV
+          //   call.
+          if (IsClaimRV) {
+            Builder.SetInsertPoint(II);
+            Function *IFn =
+                Intrinsic::getDeclaration(Mod, Intrinsic::objc_release);
+            Value *BC =
+                Builder.CreateBitCast(RetOpnd, IFn->getArg(0)->getType());
+            Builder.CreateCall(IFn, BC, "");
+          }
+          II->eraseFromParent();
+          InsertRetainCall = false;
+        }
+      } else if (auto *CI = dyn_cast<CallInst>(&*CurI)) {
+        if (objcarc::GetRCIdentityRoot(CI) == RetOpnd &&
+            !objcarc::hasAttachedCallOpBundle(CI)) {
+          // If we've found an unannotated call that defines RetOpnd, add a
+          // "clang.arc.attachedcall" operand bundle.
+          Value *BundleArgs[] = {ConstantInt::get(
+              Builder.getInt64Ty(),
+              objcarc::getAttachedCallOperandBundleEnum(IsRetainRV))};
+          OperandBundleDef OB("clang.arc.attachedcall", BundleArgs);
+          auto *NewCall = CallBase::addOperandBundle(
+              CI, LLVMContext::OB_clang_arc_attachedcall, OB, CI);
+          NewCall->copyMetadata(*CI);
+          CI->replaceAllUsesWith(NewCall);
+          CI->eraseFromParent();
+          InsertRetainCall = false;
+        }
+      }
+
+      break;
+    }
+
+    if (InsertRetainCall) {
+      // The retainRV is attached to the call and we've failed to find a
+      // matching autoreleaseRV or an annotated call in the callee. Emit a call
+      // to objc_retain.
+      Builder.SetInsertPoint(RI);
+      Function *IFn = Intrinsic::getDeclaration(Mod, Intrinsic::objc_retain);
+      Value *BC = Builder.CreateBitCast(RetOpnd, IFn->getArg(0)->getType());
+      Builder.CreateCall(IFn, BC, "");
+    }
+  }
+}
+
 /// This function inlines the called function into the basic block of the
 /// caller. This returns false if it is not possible to inline this call.
 /// The program is still in a well defined state if this occurs though.
@@ -1687,6 +1782,8 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
       // ... and "funclet" operand bundles.
       if (Tag == LLVMContext::OB_funclet)
         continue;
+      if (Tag == LLVMContext::OB_clang_arc_attachedcall)
+        continue;
 
       return InlineResult::failure("unsupported operand bundle");
     }
@@ -1853,6 +1950,10 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
     // Remember the first block that is newly cloned over.
     FirstNewBlock = LastBlock; ++FirstNewBlock;
 
+    // Insert retainRV/clainRV runtime calls.
+    if (objcarc::hasAttachedCallOpBundle(&CB))
+      inlineRetainOrClaimRVCalls(CB, Returns);
+
     if (IFI.CallerBFI != nullptr && IFI.CalleeBFI != nullptr)
       // Update the BFI of blocks cloned into the caller.
       updateCallerBFI(OrigBB, VMap, IFI.CallerBFI, IFI.CalleeBFI,

diff  --git a/llvm/test/Bitcode/operand-bundles-bc-analyzer.ll b/llvm/test/Bitcode/operand-bundles-bc-analyzer.ll
index f22fcbeb271e..cb7a3ee7eb71 100644
--- a/llvm/test/Bitcode/operand-bundles-bc-analyzer.ll
+++ b/llvm/test/Bitcode/operand-bundles-bc-analyzer.ll
@@ -9,6 +9,7 @@
 ; CHECK-NEXT:    <OPERAND_BUNDLE_TAG
 ; CHECK-NEXT:    <OPERAND_BUNDLE_TAG
 ; CHECK-NEXT:    <OPERAND_BUNDLE_TAG
+; CHECK-NEXT:    <OPERAND_BUNDLE_TAG
 ; CHECK-NEXT:  </OPERAND_BUNDLE_TAGS_BLOCK
 
 ; CHECK:   <FUNCTION_BLOCK

diff  --git a/llvm/test/CodeGen/AArch64/call-rv-marker.ll b/llvm/test/CodeGen/AArch64/call-rv-marker.ll
index 245d2c854c34..3b5ab40839b5 100644
--- a/llvm/test/CodeGen/AArch64/call-rv-marker.ll
+++ b/llvm/test/CodeGen/AArch64/call-rv-marker.ll
@@ -33,7 +33,7 @@ define dso_local i8* @rv_marker_1() {
 ; GISEL-NOT:       mov x29, x29
 ;
 entry:
-  %call = call "rv_marker" i8* @foo1()
+  %call = call i8* @foo1() [ "clang.arc.attachedcall"(i64 0) ]
   ret i8* %call
 }
 
@@ -49,7 +49,7 @@ define dso_local void @rv_marker_2_select(i32 %c) {
 entry:
   %tobool.not = icmp eq i32 %c, 0
   %.sink = select i1 %tobool.not, i32 2, i32 1
-  %call1 = call "rv_marker" i8* @foo0(i32 %.sink)
+  %call1 = call i8* @foo0(i32 %.sink) [ "clang.arc.attachedcall"(i64 0) ]
   tail call void @foo2(i8* %call1)
   ret void
 }
@@ -61,7 +61,7 @@ define dso_local void @rv_marker_3() personality i8* bitcast (i32 (...)* @__gxx_
 ; SELDAG-NEXT:   mov x29, x29
 ;
 entry:
-  %call = call "rv_marker" i8* @foo1()
+  %call = call i8* @foo1() [ "clang.arc.attachedcall"(i64 0) ]
   invoke void @objc_object(i8* %call) #5
           to label %invoke.cont unwind label %lpad
 
@@ -87,7 +87,7 @@ entry:
   %s = alloca %struct.S, align 1
   %0 = getelementptr inbounds %struct.S, %struct.S* %s, i64 0, i32 0
   call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull %0) #2
-  %call = invoke "rv_marker" i8* @foo1()
+  %call = invoke i8* @foo1() [ "clang.arc.attachedcall"(i64 0) ]
           to label %invoke.cont unwind label %lpad
 
 invoke.cont:                                      ; preds = %entry
@@ -127,12 +127,12 @@ define dso_local i8* @rv_marker_5_indirect_call() {
 ;
 entry:
   %0 = load i8* ()*, i8* ()** @fptr, align 8
-  %call = call "rv_marker" i8* %0()
+  %call = call i8* %0() [ "clang.arc.attachedcall"(i64 0) ]
   tail call void @foo2(i8* %call)
   ret i8* %call
 }
 
-declare void @foo(i64, i64, i64)
+declare i8* @foo(i64, i64, i64)
 
 define dso_local void @rv_marker_multiarg(i64 %a, i64 %b, i64 %c) {
 ; CHECK-LABEL: rv_marker_multiarg
@@ -142,7 +142,7 @@ define dso_local void @rv_marker_multiarg(i64 %a, i64 %b, i64 %c) {
 ; CHECK-NEXT:   bl  foo
 ; SELDAG-NEXT:  mov x29, x29
 ; GISEL-NOT:    mov x29, x29
-  call "rv_marker" void @foo(i64 %c, i64 %b, i64 %a)
+  call i8* @foo(i64 %c, i64 %b, i64 %a) [ "clang.arc.attachedcall"(i64 0) ]
   ret void
 }
 

diff  --git a/llvm/test/Transforms/DeadArgElim/deadretval.ll b/llvm/test/Transforms/DeadArgElim/deadretval.ll
index 5f3817c6728d..f3b343745e4d 100644
--- a/llvm/test/Transforms/DeadArgElim/deadretval.ll
+++ b/llvm/test/Transforms/DeadArgElim/deadretval.ll
@@ -1,4 +1,8 @@
-; RUN: opt < %s -deadargelim -S | not grep DEAD
+; RUN: opt < %s -deadargelim -S | FileCheck %s
+
+ at g0 = global i8 0, align 8
+
+; CHECK-NOT: DEAD
 
 ; Dead arg only used by dead retval
 define internal i32 @test(i32 %DEADARG) {
@@ -16,3 +20,22 @@ define i32 @test3() {
         ret i32 %Y
 }
 
+; The callee function's return type shouldn't be changed if the call result is
+; used.
+
+; CHECK-LABEL: define internal i8* @callee4()
+
+define internal i8* @callee4(i8* %a0) {
+  ret i8* @g0;
+}
+
+declare void @llvm.objc.clang.arc.noop.use(...)
+
+; CHECK-LABEL: define i8* @test4(
+; CHECK: tail call i8* @callee4() [ "clang.arc.attachedcall"(i64 0) ]
+
+define i8* @test4() {
+  %call = tail call i8* @callee4(i8* @g0) [ "clang.arc.attachedcall"(i64 0) ]
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %call)
+  ret i8* @g0
+}

diff  --git a/llvm/test/Transforms/Inline/inline-retainRV-call.ll b/llvm/test/Transforms/Inline/inline-retainRV-call.ll
new file mode 100644
index 000000000000..f8ac2154f933
--- /dev/null
+++ b/llvm/test/Transforms/Inline/inline-retainRV-call.ll
@@ -0,0 +1,175 @@
+; RUN: opt < %s -inline -S | FileCheck %s
+
+ at g0 = global i8* null, align 8
+declare i8* @foo0()
+
+define i8* @callee0_autoreleaseRV() {
+  %call = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+  %1 = tail call i8* @llvm.objc.autoreleaseReturnValue(i8* %call)
+  ret i8* %call
+}
+
+; CHECK-LABEL: define void @test0_autoreleaseRV(
+; CHECK: call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+
+define void @test0_autoreleaseRV() {
+  %call = call i8* @callee0_autoreleaseRV() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test0_claimRV_autoreleaseRV(
+; CHECK: %[[CALL:.*]] = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK: call void @llvm.objc.release(i8* %[[CALL]])
+; CHECK-NEXT: ret void
+
+define void @test0_claimRV_autoreleaseRV() {
+  %call = call i8* @callee0_autoreleaseRV() [ "clang.arc.attachedcall"(i64 1) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test1_autoreleaseRV(
+; CHECK: invoke i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+
+define void @test1_autoreleaseRV() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %call = invoke i8* @callee0_autoreleaseRV() [ "clang.arc.attachedcall"(i64 0) ]
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+  ret void
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+}
+
+; CHECK-LABEL: define void @test1_claimRV_autoreleaseRV(
+; CHECK: %[[INVOKE:.*]] = invoke i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK: call void @llvm.objc.release(i8* %[[INVOKE]])
+; CHECK-NEXT: br
+
+define void @test1_claimRV_autoreleaseRV() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %call = invoke i8* @callee0_autoreleaseRV() [ "clang.arc.attachedcall"(i64 1) ]
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+  ret void
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+}
+
+define i8* @callee1_no_autoreleaseRV() {
+  %call = call i8* @foo0()
+  ret i8* %call
+}
+
+; CHECK-LABEL: define void @test2_no_autoreleaseRV(
+; CHECK: call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK-NEXT: ret void
+
+define void @test2_no_autoreleaseRV() {
+  %call = call i8* @callee1_no_autoreleaseRV() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test2_claimRV_no_autoreleaseRV(
+; CHECK: call i8* @foo0() [ "clang.arc.attachedcall"(i64 1) ]
+; CHECK-NEXT: ret void
+
+define void @test2_claimRV_no_autoreleaseRV() {
+  %call = call i8* @callee1_no_autoreleaseRV() [ "clang.arc.attachedcall"(i64 1) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test3_no_autoreleaseRV(
+; CHECK: invoke i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+
+define void @test3_no_autoreleaseRV() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %call = invoke i8* @callee1_no_autoreleaseRV() [ "clang.arc.attachedcall"(i64 0) ]
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+  ret void
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+}
+
+define i8* @callee2_nocall() {
+  %1 = load i8*, i8** @g0, align 8
+  ret i8* %1
+}
+
+; Check that a call to @llvm.objc.retain is inserted if there is no matching
+; autoreleaseRV call or a call.
+
+; CHECK-LABEL: define void @test4_nocall(
+; CHECK: %[[V0:.*]] = load i8*, i8** @g0,
+; CHECK-NEXT: call i8* @llvm.objc.retain(i8* %[[V0]])
+; CHECK-NEXT: ret void
+
+define void @test4_nocall() {
+  %call = call i8* @callee2_nocall() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test4_claimRV_nocall(
+; CHECK: %[[V0:.*]] = load i8*, i8** @g0,
+; CHECK-NEXT: ret void
+
+define void @test4_claimRV_nocall() {
+  %call = call i8* @callee2_nocall() [ "clang.arc.attachedcall"(i64 1) ]
+  ret void
+}
+
+; Check that a call to @llvm.objc.retain is inserted if call to @foo already has
+; the attribute. I'm not sure this will happen in practice.
+
+define i8* @callee3_marker() {
+  %1 = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+  ret i8* %1
+}
+
+; CHECK-LABEL: define void @test5(
+; CHECK: %[[V0:.*]] = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK-NEXT: call i8* @llvm.objc.retain(i8* %[[V0]])
+; CHECK-NEXT: ret void
+
+define void @test5() {
+  %call = call i8* @callee3_marker() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+; Don't pair up an autoreleaseRV in the callee and an retainRV in the caller
+; if there is an instruction between the ret instruction and the call to
+; autoreleaseRV that isn't a cast instruction.
+
+define i8* @callee0_autoreleaseRV2() {
+  %call = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+  %1 = tail call i8* @llvm.objc.autoreleaseReturnValue(i8* %call)
+  store i8* null, i8** @g0
+  ret i8* %call
+}
+
+; CHECK-LABEL: define void @test6(
+; CHECK: %[[V0:.*]] = call i8* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK: call i8* @llvm.objc.autoreleaseReturnValue(i8* %[[V0]])
+; CHECK: store i8* null, i8** @g0, align 8
+; CHECK: call i8* @llvm.objc.retain(i8* %[[V0]])
+; CHECK-NEXT: ret void
+
+define void @test6() {
+  %call = call i8* @callee0_autoreleaseRV2() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+declare i8* @llvm.objc.autoreleaseReturnValue(i8*)
+declare i32 @__gxx_personality_v0(...)

diff  --git a/llvm/test/Transforms/ObjCARC/contract-marker-funclet.ll b/llvm/test/Transforms/ObjCARC/contract-marker-funclet.ll
index c0d6e0033dda..c40f411c9fb7 100644
--- a/llvm/test/Transforms/ObjCARC/contract-marker-funclet.ll
+++ b/llvm/test/Transforms/ObjCARC/contract-marker-funclet.ll
@@ -10,6 +10,16 @@
 ;   }
 ; }
 
+; CHECK-LABEL: define void @"\01?g@@YAXXZ"()
+; CHECK-LABEL: catch
+; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""() [ "funclet"(token %1) ]
+
+; CHECK-LABEL: catch.1
+; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""() [ "funclet"(token %1) ]
+
+; CHECK-LABEL: invoke.cont
+; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""(){{$}}
+
 define void @"\01?g@@YAXXZ"() personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
 entry:
   %call = invoke i8* @"\01?f@@YAPAUobjc_object@@XZ"()
@@ -40,23 +50,41 @@ invoke.cont:                                      ; preds = %entry
   ret void
 }
 
+; CHECK-LABEL: define dso_local void @"?test_attr_claimRV@@YAXXZ"()
+; CHECK: %[[CALL4:.*]] = notail call i8* @"?noexcept_func@@YAPAUobjc_object@@XZ"() [ "clang.arc.attachedcall"(i64 1) ]
+; CHECK: call i8* @llvm.objc.unsafeClaimAutoreleasedReturnValue(i8* %[[CALL4]])
+
+; CHECK: %[[V1:.*]] = cleanuppad
+; CHECK: %[[CALL:.*]] = notail call i8* @"?noexcept_func@@YAPAUobjc_object@@XZ"() [ "funclet"(token %[[V1]]), "clang.arc.attachedcall"(i64 1) ]
+; CHECK: call i8* @llvm.objc.unsafeClaimAutoreleasedReturnValue(i8* %[[CALL]]) [ "funclet"(token %[[V1]]) ]
+
+define dso_local void @"?test_attr_claimRV@@YAXXZ"() local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  invoke void @"?foo@@YAXXZ"()
+          to label %invoke.cont unwind label %ehcleanup
+
+invoke.cont:                                      ; preds = %entry
+  %call.i4 = tail call i8* @"?noexcept_func@@YAPAUobjc_object@@XZ"() #2 [ "clang.arc.attachedcall"(i64 1) ]
+  ret void
+
+ehcleanup:                                        ; preds = %entry
+  %0 = cleanuppad within none []
+  %call.i = call i8* @"?noexcept_func@@YAPAUobjc_object@@XZ"() #2 [ "funclet"(token %0), "clang.arc.attachedcall"(i64 1) ]
+  cleanupret from %0 unwind to caller
+}
+
 declare i8* @"\01?f@@YAPAUobjc_object@@XZ"()
 
 declare i32 @__CxxFrameHandler3(...)
 
+declare void @"?foo@@YAXXZ"()
+declare i8* @"?noexcept_func@@YAPAUobjc_object@@XZ"()
+
 declare dllimport i8* @llvm.objc.retainAutoreleasedReturnValue(i8*)
+declare i8* @llvm.objc.unsafeClaimAutoreleasedReturnValue(i8*)
 
 declare dllimport void @llvm.objc.release(i8*)
 
 !llvm.module.flags = !{!0}
 
 !0 = !{i32 1, !"clang.arc.retainAutoreleasedReturnValueMarker", !"movl\09%ebp, %ebp\09\09// marker for objc_retainAutoreleaseReturnValue"}
-
-; CHECK-LABEL: catch
-; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""() [ "funclet"(token %1) ]
-
-; CHECK-LABEL: catch.1
-; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""() [ "funclet"(token %1) ]
-
-; CHECK-LABEL: invoke.cont
-; CHECK: call void asm sideeffect "movl{{.*}}%ebp, %ebp{{.*}}", ""(){{$}}

diff  --git a/llvm/test/Transforms/ObjCARC/contract-rv-attr.ll b/llvm/test/Transforms/ObjCARC/contract-rv-attr.ll
new file mode 100644
index 000000000000..3a817327c363
--- /dev/null
+++ b/llvm/test/Transforms/ObjCARC/contract-rv-attr.ll
@@ -0,0 +1,63 @@
+; RUN: opt -objc-arc-contract -S < %s | FileCheck %s
+; RUN: opt -passes=objc-arc-contract -S < %s | FileCheck %s
+
+; CHECK-LABEL: define void @test0() {
+; CHECK: %[[CALL:.*]] = notail call i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK: call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %[[CALL]])
+
+define void @test0() {
+  %call1 = call i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}
+
+; CHECK-LABEL: define void @test1() {
+; CHECK: %[[CALL:.*]] = notail call i8* @foo() [ "clang.arc.attachedcall"(i64 1) ]
+; CHECK: call i8* @llvm.objc.unsafeClaimAutoreleasedReturnValue(i8* %[[CALL]])
+
+define void @test1() {
+  %call1 = call i8* @foo() [ "clang.arc.attachedcall"(i64 1) ]
+  ret void
+}
+
+; CHECK-LABEL:define i8* @test2(
+; CHECK: %[[CALL1:.*]] = invoke i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+
+; CHECK: %[[V0:.*]] = call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %[[CALL1]])
+; CHECK-NEXT: br
+
+; CHECK: %[[CALL3:.*]] = invoke i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+
+; CHECK: %[[V2:.*]] = call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %[[CALL3]])
+; CHECK-NEXT: br
+
+; CHECK: %[[RETVAL:.*]] = phi i8* [ %[[V0]], {{.*}} ], [ %[[V2]], {{.*}} ]
+; CHECK: ret i8* %[[RETVAL]]
+
+define i8* @test2(i1 zeroext %b) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  br i1 %b, label %if.then, label %if.end
+
+if.then:
+  %call1 = invoke i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+          to label %cleanup unwind label %lpad
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+
+if.end:
+  %call3 = invoke i8* @foo() [ "clang.arc.attachedcall"(i64 0) ]
+          to label %cleanup unwind label %lpad
+
+cleanup:
+  %retval.0 = phi i8* [ %call1, %if.then ], [ %call3, %if.end ]
+  ret i8* %retval.0
+}
+
+declare i8* @foo()
+declare i32 @__gxx_personality_v0(...)
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"clang.arc.retainAutoreleasedReturnValueMarker", !"mov\09fp, fp\09\09// marker for objc_retainAutoreleaseReturnValue"}

diff  --git a/llvm/test/Transforms/ObjCARC/contract.ll b/llvm/test/Transforms/ObjCARC/contract.ll
index d62fe221529e..36f0a842d0e6 100644
--- a/llvm/test/Transforms/ObjCARC/contract.ll
+++ b/llvm/test/Transforms/ObjCARC/contract.ll
@@ -227,7 +227,15 @@ define void @test13() {
   ret void
 }
 
+; CHECK-LABEL: define void @test14(
+; CHECK-NOT: clang.arc.noop.use
+; CHECK: ret void
+define void @test14(i8* %a, i8* %b) {
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %a, i8* %b) nounwind
+  ret void
+}
 
 declare void @llvm.objc.clang.arc.use(...) nounwind
+declare void @llvm.objc.clang.arc.noop.use(...) nounwind
 
 ; CHECK: attributes [[NUW]] = { nounwind }

diff  --git a/llvm/test/Transforms/ObjCARC/intrinsic-use.ll b/llvm/test/Transforms/ObjCARC/intrinsic-use.ll
index 6f3815113d69..bd4ac2965fb3 100644
--- a/llvm/test/Transforms/ObjCARC/intrinsic-use.ll
+++ b/llvm/test/Transforms/ObjCARC/intrinsic-use.ll
@@ -8,8 +8,10 @@ declare void @llvm.objc.release(i8*)
 declare i8* @llvm.objc.autorelease(i8*)
 
 declare void @llvm.objc.clang.arc.use(...)
+declare void @llvm.objc.clang.arc.noop.use(...)
 
 declare void @test0_helper(i8*, i8**)
+declare void @can_release(i8*)
 
 ; Ensure that we honor clang.arc.use as a use and don't miscompile
 ; the reduced test case from <rdar://13195034>.
@@ -108,6 +110,21 @@ entry:
   ret void
 }
 
+; ARC optimizer should be able to safely remove the retain/release pair as the
+; call to @llvm.objc.clang.arc.noop.use is a no-op.
+
+; CHECK-LABEL: define void @test_arc_noop_use(
+; CHECK-NEXT:    call void @can_release(i8* %x)
+; CHECK-NEXT:    call void (...) @llvm.objc.clang.arc.noop.use(
+; CHECK-NEXT:    ret void
+
+define void @test_arc_noop_use(i8** %out, i8* %x) {
+  call i8* @llvm.objc.retain(i8* %x)
+  call void @can_release(i8* %x)
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %x)
+  call void @llvm.objc.release(i8* %x), !clang.imprecise_release !0
+  ret void
+}
 
 !0 = !{}
 

diff  --git a/llvm/test/Transforms/ObjCARC/rv.ll b/llvm/test/Transforms/ObjCARC/rv.ll
index f89e9f7e39d9..29017222ebb1 100644
--- a/llvm/test/Transforms/ObjCARC/rv.ll
+++ b/llvm/test/Transforms/ObjCARC/rv.ll
@@ -11,6 +11,7 @@ declare i8* @llvm.objc.retainAutoreleaseReturnValue(i8*)
 declare void @llvm.objc.autoreleasePoolPop(i8*)
 declare void @llvm.objc.autoreleasePoolPush()
 declare i8* @llvm.objc.retainBlock(i8*)
+declare void @llvm.objc.clang.arc.noop.use(...)
 
 declare i8* @objc_retainedObject(i8*)
 declare i8* @objc_unretainedObject(i8*)
@@ -452,6 +453,32 @@ bb1:
   ret i8* %v3
 }
 
+; Remove operand bundle "clang.arc.attachedcall" and the autoreleaseRV call if the call
+; is a tail call.
+
+; CHECK-LABEL: define i8* @test31(
+; CHECK-NEXT: %[[CALL:.*]] = tail call i8* @returner()
+; CHECK-NEXT: ret i8* %[[CALL]]
+
+define i8* @test31() {
+  %call = tail call i8* @returner() [ "clang.arc.attachedcall"(i64 0) ]
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %call)
+  %1 = call i8* @llvm.objc.autoreleaseReturnValue(i8* %call)
+  ret i8* %1
+}
+
+; CHECK-LABEL: define i8* @test32(
+; CHECK: %[[CALL:.*]] = call i8* @returner() [ "clang.arc.attachedcall"(i64 0) ]
+; CHECK: call void (...) @llvm.objc.clang.arc.noop.use(i8* %[[CALL]])
+; CHECK: call i8* @llvm.objc.autoreleaseReturnValue(i8* %[[CALL]])
+
+define i8* @test32() {
+  %call = call i8* @returner() [ "clang.arc.attachedcall"(i64 0) ]
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %call)
+  %1 = call i8* @llvm.objc.autoreleaseReturnValue(i8* %call)
+  ret i8* %1
+}
+
 !0 = !{}
 
 ; CHECK: attributes [[NUW]] = { nounwind }

diff  --git a/llvm/test/Transforms/SCCP/clang-arc-rv.ll b/llvm/test/Transforms/SCCP/clang-arc-rv.ll
new file mode 100644
index 000000000000..bb8f45b41c13
--- /dev/null
+++ b/llvm/test/Transforms/SCCP/clang-arc-rv.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -ipsccp -S | FileCheck %s
+; Return value can't be zapped if there is a call that has operand bundle
+; "clang.arc.attachedcall".
+
+ at g0 = global i8 zeroinitializer, align 1
+
+; CHECK-LABEL: @foo(
+; CHECK: ret i8* @g0
+
+define internal i8* @foo() {
+  ret i8* @g0
+}
+
+; CHECK-LABEL: @test(
+; CHECK: %[[R:.*]] = call i8* @foo()
+; CHECK call void (...) @llvm.objc.clang.arc.noop.use(i8* %[[R]])
+
+define void @test() {
+  %r = call i8* @foo() [ "clang.arc.attachedcall"(i64 1) ]
+  call void (...) @llvm.objc.clang.arc.noop.use(i8* %r)
+  ret void
+}
+
+declare void @llvm.objc.clang.arc.noop.use(...)

diff  --git a/llvm/test/Transforms/TailCallElim/deopt-bundle.ll b/llvm/test/Transforms/TailCallElim/deopt-bundle.ll
index f651e462c1f5..a07584942171 100644
--- a/llvm/test/Transforms/TailCallElim/deopt-bundle.ll
+++ b/llvm/test/Transforms/TailCallElim/deopt-bundle.ll
@@ -55,3 +55,13 @@ catch:
 exit:
   ret void
 }
+
+; CHECK-LABEL: @test_clang_arc_attachedcall(
+; CHECK: tail call i8* @getObj(
+
+declare i8* @getObj()
+
+define i8* @test_clang_arc_attachedcall() {
+  %r = call i8* @getObj() [ "clang.arc.attachedcall"(i64 0) ]
+  ret i8* %r
+}

diff  --git a/llvm/test/Verifier/operand-bundles.ll b/llvm/test/Verifier/operand-bundles.ll
index 2598a7889f3f..4ef0e647988a 100644
--- a/llvm/test/Verifier/operand-bundles.ll
+++ b/llvm/test/Verifier/operand-bundles.ll
@@ -1,10 +1,13 @@
 ; RUN: not opt -verify < %s 2>&1 | FileCheck %s
 
+%0 = type opaque
+declare void @g()
+declare %0* @foo0()
+declare i8 @foo1()
+
 ; Operand bundles uses are like regular uses, and need to be dominated
 ; by their defs.
 
-declare void @g()
-
 define void @f0(i32* %ptr) {
 ; CHECK: Instruction does not dominate all uses!
 ; CHECK-NEXT:  %x = add i32 42, 1
@@ -60,3 +63,15 @@ define void @f_gc_transition(i32* %ptr) {
   %x = add i32 42, 1
   ret void
 }
+
+define void @f_clang_arc_attachedcall() {
+; CHECK: Multiple "clang.arc.attachedcall" operand bundles
+; CHECK-NEXT: call %0* @foo0() [ "clang.arc.attachedcall"(i64 0), "clang.arc.attachedcall"(i64 0) ]
+; CHECK-NEXT: must call a function returning a pointer
+; CHECK-NEXT: call i8 @foo1() [ "clang.arc.attachedcall"(i64 0) ]
+
+  call %0* @foo0() [ "clang.arc.attachedcall"(i64 0) ]
+  call %0* @foo0() [ "clang.arc.attachedcall"(i64 0), "clang.arc.attachedcall"(i64 0) ]
+  call i8 @foo1() [ "clang.arc.attachedcall"(i64 0) ]
+  ret void
+}


        


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