Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -21,13 +21,10 @@
 endif()
 
 if(NOT DEFINED LLVM_VERSION_MAJOR)
-  set(LLVM_VERSION_MAJOR 3)
+  set(LLVM_VERSION_MAJOR 4)
 endif()
 if(NOT DEFINED LLVM_VERSION_MINOR)
-  set(LLVM_VERSION_MINOR 9)
-endif()
-if(NOT DEFINED LLVM_VERSION_PATCH)
-  set(LLVM_VERSION_PATCH 0)
+  set(LLVM_VERSION_MINOR 0)
 endif()
 if(NOT DEFINED LLVM_VERSION_SUFFIX)
   set(LLVM_VERSION_SUFFIX svn)
@@ -36,13 +33,13 @@
 if (POLICY CMP0048)
   cmake_policy(SET CMP0048 NEW)
   set(cmake_3_0_PROJ_VERSION
-    VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH})
+    VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR})
   set(cmake_3_0_LANGUAGES LANGUAGES)
 endif()
 
 if (NOT PACKAGE_VERSION)
   set(PACKAGE_VERSION
-    "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}${LLVM_VERSION_SUFFIX}")
+    "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}${LLVM_VERSION_SUFFIX}")
 endif()
 
 project(LLVM
@@ -134,7 +131,6 @@
 set(CPACK_PACKAGE_VENDOR "LLVM")
 set(CPACK_PACKAGE_VERSION_MAJOR ${LLVM_VERSION_MAJOR})
 set(CPACK_PACKAGE_VERSION_MINOR ${LLVM_VERSION_MINOR})
-set(CPACK_PACKAGE_VERSION_PATCH ${LLVM_VERSION_PATCH})
 set(CPACK_PACKAGE_VERSION ${PACKAGE_VERSION})
 set(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE.TXT")
 set(CPACK_NSIS_COMPRESSOR "/SOLID lzma \r\n SetCompressorDictSize 32")
Index: cmake/modules/AddLLVM.cmake
===================================================================
--- cmake/modules/AddLLVM.cmake
+++ cmake/modules/AddLLVM.cmake
@@ -257,7 +257,7 @@
 #   VERSION_MINOR int
 #     Optional minor version number (defaults to LLVM_VERSION_MINOR)
 #   VERSION_PATCHLEVEL int
-#     Optional patchlevel version number (defaults to LLVM_VERSION_PATCH)
+#     Optional patchlevel version number (defaults to 0)
 #   VERSION_STRING
 #     Optional version string (defaults to PACKAGE_VERSION)
 #   PRODUCT_NAME
@@ -279,7 +279,7 @@
   endif()
 
   if (NOT DEFINED ARG_VERSION_PATCHLEVEL)
-    set(ARG_VERSION_PATCHLEVEL ${LLVM_VERSION_PATCH})
+    set(ARG_VERSION_PATCHLEVEL 0)
   endif()
 
   if (NOT DEFINED ARG_VERSION_STRING)
@@ -462,8 +462,8 @@
       if(${output_name} STREQUAL "output_name-NOTFOUND")
         set(output_name ${name})
       endif()
-      set(library_name ${output_name}-${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}${LLVM_VERSION_SUFFIX})
-      set(api_name ${output_name}-${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}${LLVM_VERSION_SUFFIX})
+      set(library_name ${output_name}-${LLVM_VERSION_MAJOR}${LLVM_VERSION_SUFFIX})
+      set(api_name ${output_name}-${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}${LLVM_VERSION_SUFFIX})
       set_target_properties(${name} PROPERTIES OUTPUT_NAME ${library_name})
       llvm_install_library_symlink(${api_name} ${library_name} SHARED
         COMPONENT ${name}
Index: cmake/modules/LLVMConfig.cmake.in
===================================================================
--- cmake/modules/LLVMConfig.cmake.in
+++ cmake/modules/LLVMConfig.cmake.in
@@ -4,7 +4,6 @@
 
 set(LLVM_VERSION_MAJOR @LLVM_VERSION_MAJOR@)
 set(LLVM_VERSION_MINOR @LLVM_VERSION_MINOR@)
-set(LLVM_VERSION_PATCH @LLVM_VERSION_PATCH@)
 set(LLVM_PACKAGE_VERSION @PACKAGE_VERSION@)
 
 set(LLVM_BUILD_TYPE @CMAKE_BUILD_TYPE@)
Index: cmake/modules/LLVMConfigVersion.cmake.in
===================================================================
--- cmake/modules/LLVMConfigVersion.cmake.in
+++ cmake/modules/LLVMConfigVersion.cmake.in
@@ -1,13 +1,12 @@
 set(PACKAGE_VERSION "@PACKAGE_VERSION@")
 
-# LLVM is API-compatible only with matching major.minor versions
-# and patch versions not less than that requested.
-if("@LLVM_VERSION_MAJOR@.@LLVM_VERSION_MINOR@" VERSION_EQUAL
-    "${PACKAGE_FIND_VERSION_MAJOR}.${PACKAGE_FIND_VERSION_MINOR}"
-   AND NOT "@LLVM_VERSION_PATCH@" VERSION_LESS "${PACKAGE_FIND_VERSION_PATCH}")
+# LLVM is API-compatible only with matching major versions
+# and minor versions not less than that requested.
+if("@LLVM_VERSION_MAJOR@" VERSION_EQUAL
+    "${PACKAGE_FIND_VERSION_MAJOR}"
+   AND NOT "@LLVM_VERSION_MINOR@" VERSION_LESS "${PACKAGE_FIND_VERSION_MINOR}")
   set(PACKAGE_VERSION_COMPATIBLE 1)
-  if("@LLVM_VERSION_PATCH@" VERSION_EQUAL
-      "${PACKAGE_FIND_VERSION_PATCH}")
+  if("@LLVM_VERSION_MINOR@" VERSION_EQUAL "${PACKAGE_FIND_VERSION_MINOR}")
     set(PACKAGE_VERSION_EXACT 1)
   endif()
 endif()
Index: docs/DeveloperPolicy.rst
===================================================================
--- docs/DeveloperPolicy.rst
+++ docs/DeveloperPolicy.rst
@@ -510,12 +510,11 @@
 * Additions and changes to the IR should be reflected in
   ``test/Bitcode/compatibility.ll``.
 
-* The bitcode format produced by a X.Y release will be readable by all
-  following X.Z releases and the (X+1).0 release.
+* The current LLVM version supports loading any bitcode since version 3.0.
 
-* After each X.Y release, ``compatibility.ll`` must be copied to
-  ``compatibility-X.Y.ll``. The corresponding bitcode file should be assembled
-  using the X.Y build and committed as ``compatibility-X.Y.ll.bc``.
+* After each release, ``compatibility.ll`` must be copied to
+  ``compatibility-X.ll``. The corresponding bitcode file should be assembled
+  using the X version and committed as ``compatibility-X.ll.bc``.
 
 * Newer releases can ignore features from older releases, but they cannot
   miscompile them. For example, if nsw is ever replaced with something else,
Index: docs/conf.py
===================================================================
--- docs/conf.py
+++ docs/conf.py
@@ -47,10 +47,10 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-# The short X.Y version.
-version = '3.9'
+# The short version.
+version = '4'
 # The full version, including alpha/beta/rc tags.
-release = '3.9'
+release = '4'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
Index: include/llvm/Config/config.h.cmake
===================================================================
--- include/llvm/Config/config.h.cmake
+++ include/llvm/Config/config.h.cmake
@@ -500,7 +500,7 @@
 #define LLVM_VERSION_MINOR ${LLVM_VERSION_MINOR}
 
 /* Patch version of the LLVM API */
-#define LLVM_VERSION_PATCH ${LLVM_VERSION_PATCH}
+#define LLVM_VERSION_PATCH 0
 
 /* LLVM version string */
 #define LLVM_VERSION_STRING "${PACKAGE_VERSION}"
Index: include/llvm/Config/llvm-config.h.cmake
===================================================================
--- include/llvm/Config/llvm-config.h.cmake
+++ include/llvm/Config/llvm-config.h.cmake
@@ -97,7 +97,7 @@
 #define LLVM_VERSION_MINOR ${LLVM_VERSION_MINOR}
 
 /* Patch version of the LLVM API */
-#define LLVM_VERSION_PATCH ${LLVM_VERSION_PATCH}
+#define LLVM_VERSION_PATCH 0
 
 /* LLVM version string */
 #define LLVM_VERSION_STRING "${PACKAGE_VERSION}"
Index: tools/llvm-shlib/CMakeLists.txt
===================================================================
--- tools/llvm-shlib/CMakeLists.txt
+++ tools/llvm-shlib/CMakeLists.txt
@@ -51,7 +51,7 @@
 if (APPLE)
   set_property(TARGET LLVM APPEND_STRING PROPERTY
               LINK_FLAGS
-              " -compatibility_version 1 -current_version ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}")
+              " -compatibility_version 1 -current_version ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}")
 endif()
 
 if(TARGET libLLVMExports)
@@ -90,6 +90,6 @@
   
   set_property(TARGET LLVM-C APPEND_STRING PROPERTY
               LINK_FLAGS
-              " -compatibility_version 1 -current_version ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH} -Wl,-reexport_library ${LIB_PATH}")
+              " -compatibility_version 1 -current_version ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR} -Wl,-reexport_library ${LIB_PATH}")
 endif()
 
Index: tools/lto/CMakeLists.txt
===================================================================
--- tools/lto/CMakeLists.txt
+++ tools/lto/CMakeLists.txt
@@ -28,5 +28,5 @@
   endif()
   set_property(TARGET LTO APPEND_STRING PROPERTY
               LINK_FLAGS
-              " -compatibility_version 1 -current_version ${LTO_VERSION}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}")
+              " -compatibility_version 1 -current_version ${LTO_VERSION}.${LLVM_VERSION_MINOR}")
 endif()