Index: include/clang/Basic/Attr.td
===================================================================
--- include/clang/Basic/Attr.td
+++ include/clang/Basic/Attr.td
@@ -1020,6 +1020,12 @@
   let Documentation = [Undocumented];
 }
 
+def NoTail : InheritableAttr {
+  let Spellings = [GNU<"notail">, CXX11<"clang", "notail">];
+  let Subjects = SubjectList<[Function, ObjCMethod]>;
+  let Documentation = [NoTailDocs];
+}
+
 def NoThrow : InheritableAttr {
   let Spellings = [GCC<"nothrow">, Declspec<"nothrow">];
   let Documentation = [Undocumented];
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -1612,3 +1612,10 @@
 arguments, with arbitrary offsets.
   }];
 }
+
+def NoTailDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+Tail call optimization is not performed on calls to a function marked ``notail``.
+  }];
+}
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1414,6 +1414,8 @@
       FuncAttrs.addAttribute(llvm::Attribute::NoReturn);
     if (TargetDecl->hasAttr<NoDuplicateAttr>())
       FuncAttrs.addAttribute(llvm::Attribute::NoDuplicate);
+    if (TargetDecl->hasAttr<NoTailAttr>())
+      FuncAttrs.addAttribute(llvm::Attribute::NoTail);
 
     if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) {
       const FunctionProtoType *FPT = Fn->getType()->getAs<FunctionProtoType>();
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -4878,6 +4878,9 @@
   case AttributeList::AT_ReturnsTwice:
     handleSimpleAttribute<ReturnsTwiceAttr>(S, D, Attr);
     break;
+  case AttributeList::AT_NoTail:
+    handleSimpleAttribute<NoTailAttr>(S, D, Attr);
+    break;
   case AttributeList::AT_Used:
     handleUsedAttr(S, D, Attr);
     break;
Index: test/CodeGen/attr-no-tail.c
===================================================================
--- /dev/null
+++ test/CodeGen/attr-no-tail.c
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -o - | FileCheck %s
+
+// CHECK: define i32 @callee0(i32 %a) [[ATTRNOTAIL0:#[0-9]+]] {
+// CHECK: declare i32 @callee1(i32) [[ATTRNOTAIL1:#[0-9]+]]
+// CHECK: declare i32 @callee2(i32) [[ATTRTAIL0:#[0-9]+]]
+
+int callee0(int a) __attribute__((notail)) {
+  return a + 1;
+}
+
+int callee1(int) __attribute__((notail));
+
+int callee2(int);
+
+int caller0(int a) {
+  if (a > 0)
+    return callee0(a);
+  if (a < 0)
+    return callee1(a);
+  return callee2(a);
+}
+
+// CHECK: attributes [[ATTRNOTAIL0]] = { {{.*}}notail{{.*}} }
+// CHECK: attributes [[ATTRNOTAIL1]] = { {{.*}}notail{{.*}} }
+// CHECK-NOT: attributes [[ATTRTAIL0]] = { {{.*}}notail{{.*}} }