Index: cfe/trunk/lib/CodeGen/CGCall.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGCall.cpp
+++ cfe/trunk/lib/CodeGen/CGCall.cpp
@@ -3077,10 +3077,18 @@
   // If the call returns a temporary with struct return, create a temporary
   // alloca to hold the result, unless one is given to us.
   llvm::Value *SRetPtr = nullptr;
+  size_t UnusedReturnSize = 0;
   if (RetAI.isIndirect() || RetAI.isInAlloca()) {
     SRetPtr = ReturnValue.getValue();
-    if (!SRetPtr)
+    if (!SRetPtr) {
       SRetPtr = CreateMemTemp(RetTy);
+      if (HaveInsertPoint()) {
+        uint64_t size =
+            CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy));
+        if (EmitLifetimeStart(size, SRetPtr))
+          UnusedReturnSize = size;
+      }
+    }
     if (IRFunctionArgs.hasSRetArg()) {
       IRCallArgs[IRFunctionArgs.getSRetArgNo()] = SRetPtr;
     } else {
@@ -3412,6 +3420,10 @@
   // insertion point; this allows the rest of IRgen to discard
   // unreachable code.
   if (CS.doesNotReturn()) {
+    if (UnusedReturnSize)
+      EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
+                      SRetPtr);
+
     Builder.CreateUnreachable();
     Builder.ClearInsertionPoint();
 
@@ -3440,8 +3452,13 @@
   RValue Ret = [&] {
     switch (RetAI.getKind()) {
     case ABIArgInfo::InAlloca:
-    case ABIArgInfo::Indirect:
-      return convertTempToRValue(SRetPtr, RetTy, SourceLocation());
+    case ABIArgInfo::Indirect: {
+      RValue ret = convertTempToRValue(SRetPtr, RetTy, SourceLocation());
+      if (UnusedReturnSize)
+        EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
+                        SRetPtr);
+      return ret;
+    }
 
     case ABIArgInfo::Ignore:
       // If we are ignoring an argument that had a result, make sure to
Index: cfe/trunk/test/CodeGenCXX/stack-reuse.cpp
===================================================================
--- cfe/trunk/test/CodeGenCXX/stack-reuse.cpp
+++ cfe/trunk/test/CodeGenCXX/stack-reuse.cpp
@@ -0,0 +1,125 @@
+// RUN: %clang -target armv7l-unknown-linux-gnueabihf -S %s -o - -emit-llvm -O1 -disable-llvm-optzns | FileCheck %s
+
+// Stack should be reused when possible, no need to allocate two separate slots
+// if they have disjoint lifetime.
+
+// Sizes of objects are related to previously existed threshold of 32.  In case
+// of S_large stack size is rounded to 40 bytes.
+
+// 32B
+struct S_small {
+  int a[8];
+};
+
+// 36B
+struct S_large {
+  int a[9];
+};
+
+extern S_small foo_small();
+extern S_large foo_large();
+extern void bar_small(S_small*);
+extern void bar_large(S_large*);
+
+// Prevent mangling of function names.
+extern "C" {
+
+void small_rvoed_unnamed_temporary_object() {
+// CHECK-LABEL: define void @small_rvoed_unnamed_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+
+  foo_small();
+  foo_small();
+}
+
+void large_rvoed_unnamed_temporary_object() {
+// CHECK-LABEL: define void @large_rvoed_unnamed_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+
+  foo_large();
+  foo_large();
+}
+
+void small_rvoed_named_temporary_object() {
+// CHECK-LABEL: define void @small_rvoed_named_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+
+  {
+    S_small s = foo_small();
+  }
+  {
+    S_small s = foo_small();
+  }
+}
+
+void large_rvoed_named_temporary_object() {
+// CHECK-LABEL: define void @large_rvoed_named_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+
+  {
+    S_large s = foo_large();
+  }
+  {
+    S_large s = foo_large();
+  }
+}
+
+void small_auto_object() {
+// CHECK-LABEL: define void @small_auto_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_smallP7S_small
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_smallP7S_small
+// CHECK: call void @llvm.lifetime.end
+
+  {
+    S_small s;
+    bar_small(&s);
+  }
+  {
+    S_small s;
+    bar_small(&s);
+  }
+}
+
+void large_auto_object() {
+// CHECK-LABEL: define void @large_auto_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_largeP7S_large
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_largeP7S_large
+// CHECK: call void @llvm.lifetime.end
+
+  {
+    S_large s;
+    bar_large(&s);
+  }
+  {
+    S_large s;
+    bar_large(&s);
+  }
+}
+
+}