Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -76,6 +76,7 @@
 -----------------------
 
 - ``clang -dumpversion`` now returns the version of Clang itself.
+  Similarly, `__VERSION__` returns the Clang version instead of 4.2.1.
 
 - ...
 
Index: lib/Frontend/InitPreprocessor.cpp
===================================================================
--- lib/Frontend/InitPreprocessor.cpp
+++ lib/Frontend/InitPreprocessor.cpp
@@ -604,11 +604,11 @@
   // Support for #pragma redefine_extname (Sun compatibility)
   Builder.defineMacro("__PRAGMA_REDEFINE_EXTNAME", "1");
 
-  // As sad as it is, enough software depends on the __VERSION__ for version
-  // checks that it is necessary to report 4.2.1 (the base GCC version we claim
-  // compatibility with) first.
-  Builder.defineMacro("__VERSION__", "\"4.2.1 Compatible " +
-                      Twine(getClangFullCPPVersion()) + "\"");
+  // We used to report 4.2.1 for compatibility with GCC.
+  // Now, we return the Clang version.
+  Builder.defineMacro("__VERSION__", "\"" CLANG_VERSION_STRING
+                      " Compatible " + Twine(getClangFullCPPVersion()) +
+                      "\"");
 
   // Initialize language-specific preprocessor defines.
 
Index: test/Preprocessor/init.c
===================================================================
--- test/Preprocessor/init.c
+++ test/Preprocessor/init.c
@@ -8169,7 +8169,7 @@
 // SPARC:#define __UINT_LEAST8_MAX__ 255
 // SPARC:#define __UINT_LEAST8_TYPE__ unsigned char
 // SPARC:#define __USER_LABEL_PREFIX__
-// SPARC:#define __VERSION__ "4.2.1 Compatible{{.*}}
+// SPARC:#define __VERSION__ "{{[0-9]+\.[0-9.]+}} Compatible{{.*}}
 // SPARC:#define __WCHAR_MAX__ 2147483647
 // SPARC:#define __WCHAR_TYPE__ int
 // SPARC:#define __WCHAR_WIDTH__ 32
@@ -9041,7 +9041,7 @@
 // X86_64-CLOUDABI:#define __UINT_LEAST8_MAX__ 255
 // X86_64-CLOUDABI:#define __UINT_LEAST8_TYPE__ unsigned char
 // X86_64-CLOUDABI:#define __USER_LABEL_PREFIX__
-// X86_64-CLOUDABI:#define __VERSION__ "4.2.1 Compatible{{.*}}
+// X86_64-CLOUDABI:#define __VERSION__ "{{[0-9]+\.[0-9.]+}} Compatible{{.*}}
 // X86_64-CLOUDABI:#define __WCHAR_MAX__ 2147483647
 // X86_64-CLOUDABI:#define __WCHAR_TYPE__ int
 // X86_64-CLOUDABI:#define __WCHAR_WIDTH__ 32