Index: include/clang/Basic/TargetInfo.h
===================================================================
--- include/clang/Basic/TargetInfo.h
+++ include/clang/Basic/TargetInfo.h
@@ -448,6 +448,9 @@
   /// \brief Return the maximum width lock-free atomic operation which can be
   /// inlined given the supported features of the given target.
   unsigned getMaxAtomicInlineWidth() const { return MaxAtomicInlineWidth; }
+  /// \brief Set the maximum inline or promote width lock-free atomic operation
+  /// for the given target.
+  virtual void setMaxAtomicWidth() {}
   /// \brief Returns true if the given target supports lock-free atomic
   /// operations at the specified width and alignment.
   virtual bool hasBuiltinAtomic(uint64_t AtomicSizeInBits,
Index: lib/Basic/Targets.cpp
===================================================================
--- lib/Basic/Targets.cpp
+++ lib/Basic/Targets.cpp
@@ -620,6 +620,7 @@
 
   Target->setSupportedOpenCLOpts();
   Target->setOpenCLExtensionOpts();
+  Target->setMaxAtomicWidth();
 
   if (!Target->validateTarget(Diags))
     return nullptr;
Index: lib/Basic/Targets/X86.h
===================================================================
--- lib/Basic/Targets/X86.h
+++ lib/Basic/Targets/X86.h
@@ -834,7 +834,7 @@
 
     // x86-64 has atomics up to 16 bytes.
     MaxAtomicPromoteWidth = 128;
-    MaxAtomicInlineWidth = 128;
+    MaxAtomicInlineWidth = 64;
   }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
@@ -892,6 +892,12 @@
                                                          HasSizeMismatch);
   }
 
+  void setMaxAtomicWidth() override {
+    if (hasFeature("cx16"))
+      MaxAtomicInlineWidth = 128;
+    return;
+  }
+
   ArrayRef<Builtin::Info> getTargetBuiltins() const override;
 };
 
Index: test/CodeGenCXX/atomic-inline.cpp
===================================================================
--- test/CodeGenCXX/atomic-inline.cpp
+++ test/CodeGenCXX/atomic-inline.cpp
@@ -0,0 +1,69 @@
+// RUN: %clang_cc1 %s -std=c++11 -emit-llvm -o - -triple=x86_64-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -std=c++11 -emit-llvm -o - -triple=x86_64-linux-gnu -target-cpu core2 | FileCheck %s --check-prefix=CORE2
+// Check the atomic code generation for cpu targets w/wo cx16 support.
+
+struct alignas(8) AM8 {
+  int f1, f2;
+};
+AM8 m8;
+AM8 load8() {
+  AM8 am;
+  // CHECK-LABEL: @_Z5load8v
+  // CHECK: load atomic i64, {{.*}} monotonic
+  // CORE2-LABEL: @_Z5load8v
+  // CORE2: load atomic i64, {{.*}} monotonic
+  __atomic_load(&m8, &am, 0);
+  return am;
+}
+
+AM8 s8;
+void store8() {
+  // CHECK-LABEL: @_Z6store8v
+  // CHECK: store atomic i64 {{.*}} monotonic
+  // CORE2-LABEL: @_Z6store8v
+  // CORE2: store atomic i64 {{.*}} monotonic
+  __atomic_store(&m8, &s8, 0);
+}
+
+bool cmpxchg8() {
+  AM8 am;
+  // CHECK-LABEL: @_Z8cmpxchg8v
+  // CHECK: cmpxchg i64* {{.*}} monotonic
+  // CORE2-LABEL: @_Z8cmpxchg8v
+  // CORE2: cmpxchg i64* {{.*}} monotonic
+  return __atomic_compare_exchange(&m8, &s8, &am, 0, 0, 0);
+}
+
+struct alignas(16) AM16 {
+  long f1, f2;
+};
+
+AM16 m16;
+AM16 load16() {
+  AM16 am;
+  // CHECK-LABEL: @_Z6load16v
+  // CHECK: call void @__atomic_load
+  // CORE2-LABEL: @_Z6load16v
+  // CORE2: load atomic i128, {{.*}} monotonic
+  __atomic_load(&m16, &am, 0);
+  return am;
+}
+
+AM16 s16;
+void store16() {
+  // CHECK-LABEL: @_Z7store16v
+  // CHECK: call void @__atomic_store
+  // CORE2-LABEL: @_Z7store16v
+  // CORE2: store atomic i128 {{.*}} monotonic
+  __atomic_store(&m16, &s16, 0);
+}
+
+bool cmpxchg16() {
+  AM16 am;
+  // CHECK-LABEL: @_Z9cmpxchg16v
+  // CHECK: call zeroext i1 @__atomic_compare_exchange
+  // CORE2-LABEL: @_Z9cmpxchg16v
+  // CORE2: cmpxchg i128* {{.*}} monotonic
+  return __atomic_compare_exchange(&m16, &s16, &am, 0, 0, 0);
+}
+
Index: test/OpenMP/atomic_capture_codegen.cpp
===================================================================
--- test/OpenMP/atomic_capture_codegen.cpp
+++ test/OpenMP/atomic_capture_codegen.cpp
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -target-cpu core2 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
 // expected-no-diagnostics
 #ifndef HEADER
 #define HEADER
Index: test/OpenMP/atomic_read_codegen.c
===================================================================
--- test/OpenMP/atomic_read_codegen.c
+++ test/OpenMP/atomic_read_codegen.c
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -target-cpu core2 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
 // expected-no-diagnostics
 // REQUIRES: x86-registered-target
 #ifndef HEADER
Index: test/OpenMP/atomic_update_codegen.cpp
===================================================================
--- test/OpenMP/atomic_update_codegen.cpp
+++ test/OpenMP/atomic_update_codegen.cpp
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -target-cpu core2 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
 // expected-no-diagnostics
 #ifndef HEADER
 #define HEADER
Index: test/OpenMP/atomic_write_codegen.c
===================================================================
--- test/OpenMP/atomic_write_codegen.c
+++ test/OpenMP/atomic_write_codegen.c
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -emit-pch -o %t %s
-// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -target-cpu core2 -fopenmp -x c -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c -triple x86_64-apple-darwin10 -target-cpu core2 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
 // expected-no-diagnostics
 // REQUIRES: x86-registered-target
 #ifndef HEADER