diff --git a/clang/lib/Headers/opencl-c.h b/clang/lib/Headers/opencl-c.h
--- a/clang/lib/Headers/opencl-c.h
+++ b/clang/lib/Headers/opencl-c.h
@@ -13832,6 +13832,7 @@
 #endif // defined(__opencl_c_ext_fp32_global_atomic_min_max) &&                \
     defined(__opencl_c_ext_fp32_local_atomic_min_max)
 
+#if defined(cl_khr_int64_base_atomics) && defined(cl_khr_int64_extended_atomics)
 #if defined(__opencl_c_ext_fp64_global_atomic_min_max)
 double __ovld atomic_fetch_min(volatile __global atomic_double *object,
                                double operand);
@@ -13882,6 +13883,8 @@
                                         memory_scope scope);
 #endif // defined(__opencl_c_ext_fp64_global_atomic_min_max) &&                \
     defined(__opencl_c_ext_fp64_local_atomic_min_max)
+#endif // defined(cl_khr_int64_base_atomics) &&
+       // defined(cl_khr_int64_extended_atomics)
 
 #if defined(__opencl_c_ext_fp16_global_atomic_add)
 half __ovld atomic_fetch_add(volatile __global atomic_half *object,
@@ -13985,6 +13988,7 @@
 #endif // defined(__opencl_c_ext_fp32_global_atomic_add) &&                    \
     defined(__opencl_c_ext_fp32_local_atomic_add)
 
+#if defined(cl_khr_int64_base_atomics) && defined(cl_khr_int64_extended_atomics)
 #if defined(__opencl_c_ext_fp64_global_atomic_add)
 double __ovld atomic_fetch_add(volatile __global atomic_double *object,
                                double operand);
@@ -14035,6 +14039,8 @@
                                         memory_scope scope);
 #endif // defined(__opencl_c_ext_fp64_global_atomic_add) &&                    \
     defined(__opencl_c_ext_fp64_local_atomic_add)
+#endif // defined(cl_khr_int64_base_atomics) &&
+       // defined(cl_khr_int64_extended_atomics)
 
 #endif // cl_ext_float_atomics
 
diff --git a/clang/lib/Sema/OpenCLBuiltins.td b/clang/lib/Sema/OpenCLBuiltins.td
--- a/clang/lib/Sema/OpenCLBuiltins.td
+++ b/clang/lib/Sema/OpenCLBuiltins.td
@@ -95,22 +95,22 @@
 def FuncExtFloatAtomicsFp16GenericLoadStore : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_global_atomic_load_store __opencl_c_ext_fp16_local_atomic_load_store">;
 def FuncExtFloatAtomicsFp16GlobalAdd     : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_global_atomic_add">;
 def FuncExtFloatAtomicsFp32GlobalAdd     : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_global_atomic_add">;
-def FuncExtFloatAtomicsFp64GlobalAdd     : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_global_atomic_add">;
+def FuncExtFloatAtomicsFp64GlobalAdd     : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_global_atomic_add">;
 def FuncExtFloatAtomicsFp16LocalAdd      : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_local_atomic_add">;
 def FuncExtFloatAtomicsFp32LocalAdd      : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_local_atomic_add">;
-def FuncExtFloatAtomicsFp64LocalAdd      : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_local_atomic_add">;
+def FuncExtFloatAtomicsFp64LocalAdd      : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_local_atomic_add">;
 def FuncExtFloatAtomicsFp16GenericAdd    : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_local_atomic_add __opencl_c_ext_fp16_global_atomic_add">;
 def FuncExtFloatAtomicsFp32GenericAdd    : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_local_atomic_add __opencl_c_ext_fp32_global_atomic_add">;
-def FuncExtFloatAtomicsFp64GenericAdd    : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_local_atomic_add __opencl_c_ext_fp64_global_atomic_add">;
+def FuncExtFloatAtomicsFp64GenericAdd    : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_local_atomic_add __opencl_c_ext_fp64_global_atomic_add">;
 def FuncExtFloatAtomicsFp16GlobalMinMax  : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_global_atomic_min_max">;
 def FuncExtFloatAtomicsFp32GlobalMinMax  : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_global_atomic_min_max">;
-def FuncExtFloatAtomicsFp64GlobalMinMax  : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_global_atomic_min_max">;
+def FuncExtFloatAtomicsFp64GlobalMinMax  : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_global_atomic_min_max">;
 def FuncExtFloatAtomicsFp16LocalMinMax   : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_local_atomic_min_max">;
 def FuncExtFloatAtomicsFp32LocalMinMax   : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_local_atomic_min_max">;
-def FuncExtFloatAtomicsFp64LocalMinMax   : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_local_atomic_min_max">;
+def FuncExtFloatAtomicsFp64LocalMinMax   : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_local_atomic_min_max">;
 def FuncExtFloatAtomicsFp16GenericMinMax : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp16_local_atomic_min_max __opencl_c_ext_fp16_global_atomic_min_max">;
 def FuncExtFloatAtomicsFp32GenericMinMax : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp32_local_atomic_min_max __opencl_c_ext_fp32_global_atomic_min_max">;
-def FuncExtFloatAtomicsFp64GenericMinMax : FunctionExtension<"cl_ext_float_atomics __opencl_c_ext_fp64_local_atomic_min_max __opencl_c_ext_fp64_global_atomic_min_max">;
+def FuncExtFloatAtomicsFp64GenericMinMax : FunctionExtension<"cl_ext_float_atomics cl_khr_int64_base_atomics cl_khr_int64_extended_atomics __opencl_c_ext_fp64_local_atomic_min_max __opencl_c_ext_fp64_global_atomic_min_max">;
 
 // Not a real extension, but a workaround to add C++ for OpenCL specific builtins.
 def FuncExtOpenCLCxx                     : FunctionExtension<"__cplusplus">;