Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -8284,9 +8284,9 @@
   "return value cannot be qualified with address space">;
 def err_opencl_constant_no_init : Error<
   "variable in constant address space must be initialized">;
-def err_atomic_init_constant : Error<
-  "atomic variable can only be assigned to a compile time constant"
-  " in the declaration statement in the program scope">;
+def err_opencl_atomic_init: Error<
+  "atomic variable can %select{only be assigned to a compile time constant|"
+  "be initialized to a variable only in global address space}0">;
 def err_opencl_implicit_vector_conversion : Error<
   "implicit conversions between vector types (%0 and %1) are not permitted">;
 def err_opencl_invalid_type_array : Error<
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11112,7 +11112,7 @@
     if (LHSTy->isAtomicType() || RHSTy->isAtomicType()) {
       SourceRange SR(LHSExpr->getLocStart(), RHSExpr->getLocEnd());
       if (BO_Assign == Opc)
-        Diag(OpLoc, diag::err_atomic_init_constant) << SR;
+        Diag(OpLoc, diag::err_opencl_atomic_init) << 0 << SR;
       else
         ResultTy = InvalidOperands(OpLoc, LHS, RHS);
       return ExprError();
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -6502,6 +6502,20 @@
       << Init->getSourceRange();
   }
 
+  // OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
+  QualType ETy = Entity.getType();
+  Qualifiers TyQualifiers = ETy.getQualifiers();
+  bool HasGlobalAS = TyQualifiers.hasAddressSpace() &&
+                     TyQualifiers.getAddressSpace() == LangAS::opencl_global;
+
+  if (S.getLangOpts().OpenCLVersion >= 200 &&
+      ETy->isAtomicType() && !HasGlobalAS &&
+      Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
+    S.Diag(Args[0]->getLocStart(), diag::err_opencl_atomic_init) << 1 <<
+    SourceRange(Entity.getDecl()->getLocStart(), Args[0]->getLocEnd());
+    return ExprError();
+  }
+
   // Diagnose cases where we initialize a pointer to an array temporary, and the
   // pointer obviously outlives the temporary.
   if (Args.size() == 1 && Args[0]->getType()->isArrayType() &&
Index: test/Parser/opencl-atomics-cl20.cl
===================================================================
--- test/Parser/opencl-atomics-cl20.cl
+++ test/Parser/opencl-atomics-cl20.cl
@@ -67,7 +67,7 @@
   foo(&i);
 // OpenCL v2.0 s6.13.11.8, arithemtic operations are not permitted on atomic types.
   i++; // expected-error {{invalid argument type 'atomic_int' (aka '_Atomic(int)') to unary expression}}
-  i = 1; // expected-error {{atomic variable can only be assigned to a compile time constant in the declaration statement in the program scope}}
+  i = 1; // expected-error {{atomic variable can only be assigned to a compile time constant}}
   i += 1; // expected-error {{invalid operands to binary expression ('atomic_int' (aka '_Atomic(int)') and 'int')}}
   i = i + i; // expected-error {{invalid operands to binary expression ('atomic_int' (aka '_Atomic(int)') and 'atomic_int')}}
 }
Index: test/SemaOpenCL/atomic-init.cl
===================================================================
--- /dev/null
+++ test/SemaOpenCL/atomic-init.cl
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -O0 -cl-std=CL2.0 -fsyntax-only -verify  %s
+
+global atomic_int a1 = 0;
+
+kernel void test_atomic_initialization() {
+  a1 = 1; // expected-error {{atomic variable can only be assigned to a compile time constant}}
+  atomic_int a2 = 0; // expected-error {{atomic variable can be initialized to a variable only in global address space}}
+  private atomic_int a3 = 0; // expected-error {{atomic variable can be initialized to a variable only in global address space}}
+  local atomic_int a4 = 0; // expected-error {{'__local' variable cannot have an initializer}}
+  global atomic_int a5 = 0; // expected-error {{function scope variable cannot be declared in global address space}}
+  static global atomic_int a6 = 0;
+}