Index: lib/Frontend/InitPreprocessor.cpp
===================================================================
--- lib/Frontend/InitPreprocessor.cpp
+++ lib/Frontend/InitPreprocessor.cpp
@@ -408,6 +408,43 @@
   if (LangOpts.ObjC1)
     Builder.defineMacro("__OBJC__");
 
+  // OpenCL v1.0/1.1 s6.9, v1.2/2.0 s6.10: Preprocessor Directives and Macros.
+  if (LangOpts.OpenCL) {
+    // OpenCL v1.0 and v1.1 do not have a predefined macro to indicate the
+    // language standard with which the program is compiled. __OPENCL_VERSION__
+    // is for the OpenCL version supported by the OpenCL device, which is not
+    // necessarily the language standard with which the program is compiled.
+    // A shared OpenCL header file requires a macro to indicate the language
+    // standard. As a workaround, __CLANG_OPENCL_C_VERSION__ is defined for
+    // OpenCL v1.0 and v1.1.
+    switch (LangOpts.OpenCLVersion) {
+    case 0:
+    case 100:
+      Builder.defineMacro("__CLANG_OPENCL_C_VERSION__", "100");
+      break;
+    case 110:
+      Builder.defineMacro("__CLANG_OPENCL_C_VERSION__", "110");
+      break;
+    case 120:
+      Builder.defineMacro("__OPENCL_C_VERSION__", "120");
+      break;
+    case 200:
+      Builder.defineMacro("__OPENCL_C_VERSION__", "200");
+      break;
+    default:
+      llvm_unreachable("Unsupported OpenCL version");
+    }
+    Builder.defineMacro("CL_VERSION_1_0", "100");
+    if (LangOpts.OpenCLVersion >= 110)
+      Builder.defineMacro("CL_VERSION_1_1", "110");
+    if (LangOpts.OpenCLVersion >= 120)
+      Builder.defineMacro("CL_VERSION_1_2", "120");
+    if (LangOpts.OpenCLVersion >= 200)
+      Builder.defineMacro("CL_VERSION_2_0", "200");
+
+    if (LangOpts.FastRelaxedMath)
+      Builder.defineMacro("__FAST_RELAXED_MATH__");
+  }
   // Not "standard" per se, but available even with the -undef flag.
   if (LangOpts.AsmPreprocessor)
     Builder.defineMacro("__ASSEMBLER__");
Index: test/Preprocessor/predefined-macros.c
===================================================================
--- test/Preprocessor/predefined-macros.c
+++ test/Preprocessor/predefined-macros.c
@@ -146,3 +146,30 @@
 // CHECK-SYNC_CAS_MIPS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
 // CHECK-SYNC_CAS_MIPS32-NOT: __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
 // CHECK-SYNC_CAS_MIPS64: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
+
+// RUN: %clang_cc1 %s -E -dM -o - -x cl \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-CL10
+// RUN: %clang_cc1 %s -E -dM -o - -x cl -cl-std=CL1.1 \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-CL11
+// RUN: %clang_cc1 %s -E -dM -o - -x cl -cl-std=CL1.2 \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-CL12
+// RUN: %clang_cc1 %s -E -dM -o - -x cl -cl-std=CL2.0 \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-CL20
+// RUN: %clang_cc1 %s -E -dM -o - -x cl -cl-fast-relaxed-math \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-FRM
+// CHECK-CL10: #define CL_VERSION_1_0 100
+// CHECK-CL10: #define __CLANG_OPENCL_C_VERSION__ 100
+// CHECK-CL11: #define CL_VERSION_1_0 100
+// CHECK-CL11: #define CL_VERSION_1_1 110
+// CHECK-CL11: #define __CLANG_OPENCL_C_VERSION__ 110
+// CHECK-CL12: #define CL_VERSION_1_0 100
+// CHECK-CL12: #define CL_VERSION_1_1 110
+// CHECK-CL12: #define CL_VERSION_1_2 120
+// CHECK-CL12: #define __OPENCL_C_VERSION__ 120
+// CHECK-CL20: #define CL_VERSION_1_0 100
+// CHECK-CL20: #define CL_VERSION_1_1 110
+// CHECK-CL20: #define CL_VERSION_1_2 120
+// CHECK-CL20: #define CL_VERSION_2_0 200
+// CHECK-CL20: #define __OPENCL_C_VERSION__ 200
+// CHECK-FRM: #define __FAST_RELAXED_MATH__ 1
+