Index: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGObjCMac.cpp
+++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp
@@ -1678,7 +1678,10 @@
 
   /// Complete the null-return operation.  It is valid to call this
   /// regardless of whether 'init' has been called.
-  RValue complete(CodeGenFunction &CGF, RValue result, QualType resultType,
+  RValue complete(CodeGenFunction &CGF,
+                  ReturnValueSlot returnSlot,
+                  RValue result,
+                  QualType resultType,
                   const CallArgList &CallArgs,
                   const ObjCMethodDecl *Method) {
     // If we never had to do a null-check, just use the raw result.
@@ -1745,7 +1748,8 @@
     // memory or (2) agg values in registers.
     if (result.isAggregate()) {
       assert(result.isAggregate() && "null init of non-aggregate result?");
-      CGF.EmitNullInitialization(result.getAggregateAddress(), resultType);
+      if (!returnSlot.isUnused())
+        CGF.EmitNullInitialization(result.getAggregateAddress(), resultType);
       if (contBB) CGF.EmitBlock(contBB);
       return result;
     }
@@ -2117,11 +2121,11 @@
     }
   }
 
-  NullReturnState nullReturn;
+  bool RequiresNullCheck = false;
 
   llvm::Constant *Fn = nullptr;
   if (CGM.ReturnSlotInterferesWithArgs(MSI.CallInfo)) {
-    if (ReceiverCanBeNull) nullReturn.init(CGF, Arg0);
+    if (ReceiverCanBeNull) RequiresNullCheck = true;
     Fn = (ObjCABI == 2) ?  ObjCTypes.getSendStretFn2(IsSuper)
       : ObjCTypes.getSendStretFn(IsSuper);
   } else if (CGM.ReturnTypeUsesFPRet(ResultType)) {
@@ -2134,23 +2138,30 @@
     // arm64 uses objc_msgSend for stret methods and yet null receiver check
     // must be made for it.
     if (ReceiverCanBeNull && CGM.ReturnTypeUsesSRet(MSI.CallInfo))
-      nullReturn.init(CGF, Arg0);
+      RequiresNullCheck = true;
     Fn = (ObjCABI == 2) ? ObjCTypes.getSendFn2(IsSuper)
       : ObjCTypes.getSendFn(IsSuper);
   }
 
+  // We don't need to emit a null check to zero out an indirect result if the
+  // result is ignored.
+  if (Return.isUnused())
+    RequiresNullCheck = false;
+
   // Emit a null-check if there's a consumed argument other than the receiver.
-  bool RequiresNullCheck = false;
-  if (ReceiverCanBeNull && CGM.getLangOpts().ObjCAutoRefCount && Method) {
+  if (!RequiresNullCheck && CGM.getLangOpts().ObjCAutoRefCount && Method) {
     for (const auto *ParamDecl : Method->parameters()) {
       if (ParamDecl->hasAttr<NSConsumedAttr>()) {
-        if (!nullReturn.NullBB)
-          nullReturn.init(CGF, Arg0);
         RequiresNullCheck = true;
         break;
       }
     }
   }
+
+  NullReturnState nullReturn;
+  if (RequiresNullCheck) {
+    nullReturn.init(CGF, Arg0);
+  }
   
   llvm::Instruction *CallSite;
   Fn = llvm::ConstantExpr::getBitCast(Fn, MSI.MessengerType);
@@ -2164,7 +2175,7 @@
     llvm::CallSite(CallSite).setDoesNotReturn();
   }
 
-  return nullReturn.complete(CGF, rvalue, ResultType, CallArgs,
+  return nullReturn.complete(CGF, Return, rvalue, ResultType, CallArgs,
                              RequiresNullCheck ? Method : nullptr);
 }
 
@@ -7073,7 +7084,7 @@
   CGCallee callee(CGCalleeInfo(), calleePtr);
 
   RValue result = CGF.EmitCall(MSI.CallInfo, callee, returnSlot, args);
-  return nullReturn.complete(CGF, result, resultType, formalArgs,
+  return nullReturn.complete(CGF, returnSlot, result, resultType, formalArgs,
                              requiresnullCheck ? method : nullptr);
 }
 
Index: cfe/trunk/test/CodeGenObjC/stret-1.m
===================================================================
--- cfe/trunk/test/CodeGenObjC/stret-1.m
+++ cfe/trunk/test/CodeGenObjC/stret-1.m
@@ -12,11 +12,20 @@
 
 int main(int argc, const char **argv)
 {
-    [(id)(argc&~255) method];
+    struct stret s;
+    s = [(id)(argc&~255) method];
     // CHECK: call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (%struct.stret*, i8*, i8*)*)(%struct.stret* sret [[T0:%[^,]+]]
     // CHECK: [[T0P:%.*]] = bitcast %struct.stret* [[T0]] to i8*
     // CHECK: call void @llvm.memset.p0i8.i64(i8* [[T0P]], i8 0, i64 400, i32 4, i1 false)
 
+    s = [Test method];
+    // CHECK: call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (%struct.stret*, i8*, i8*)*)(%struct.stret* sret [[T1:%[^,]+]]
+    // CHECK-NOT: call void @llvm.memset.p0i8.i64(
+
+    [(id)(argc&~255) method];
+    // CHECK: call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (%struct.stret*, i8*, i8*)*)(%struct.stret* sret [[T1:%[^,]+]]
+    // CHECK-NOT: call void @llvm.memset.p0i8.i64(
+
     [Test method];
     // CHECK: call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (%struct.stret*, i8*, i8*)*)(%struct.stret* sret [[T1:%[^,]+]]
     // CHECK-NOT: call void @llvm.memset.p0i8.i64(
Index: cfe/trunk/test/CodeGenObjC/stret-lifetime.m
===================================================================
--- cfe/trunk/test/CodeGenObjC/stret-lifetime.m
+++ cfe/trunk/test/CodeGenObjC/stret-lifetime.m
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -triple arm64-apple-darwin    -S -emit-llvm -o - -O2 -disable-llvm-passes %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -S -emit-llvm -o - -O2 -disable-llvm-passes %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-darwin    -fobjc-arc -S -emit-llvm -o - -O2 -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,ARC
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fobjc-arc -S -emit-llvm -o - -O2 -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,ARC
+
+struct stret { int x[100]; };
+struct stret one = {{1}};
+
+@interface Test
++(struct stret) method;
++(struct stret) methodConsuming:(id __attribute__((ns_consumed)))consumed;
+@end
+
+void foo(id o, id p) {
+  [o method];
+  // CHECK: @llvm.lifetime.start
+  // CHECK: call void bitcast {{.*}} @objc_msgSend
+  // CHECK: @llvm.lifetime.end
+  // CHECK-NOT: call void @llvm.memset
+
+  [o methodConsuming:p];
+  // ARC: [[T0:%.*]] = icmp eq i8*
+  // ARC: br i1 [[T0]]
+
+  // CHECK: @llvm.lifetime.start
+  // CHECK: call void bitcast {{.*}} @objc_msgSend
+  // CHECK: @llvm.lifetime.end
+  // ARC: br label
+
+  // ARC: call void @objc_release
+  // ARC: br label
+
+  // CHECK-NOT: call void @llvm.memset
+}