Index: llvm/trunk/cmake/modules/AddSphinxTarget.cmake
===================================================================
--- llvm/trunk/cmake/modules/AddSphinxTarget.cmake
+++ llvm/trunk/cmake/modules/AddSphinxTarget.cmake
@@ -53,8 +53,15 @@
                 DESTINATION share/man/man1)
 
       elseif (builder STREQUAL html)
-        install(DIRECTORY "${SPHINX_BUILD_DIR}"
-                DESTINATION "share/doc/${project}")
+        string(TOUPPER "${project}" project_upper)
+        set(${project_upper}_INSTALL_SPHINX_HTML_DIR "share/doc/${project}/html"
+            CACHE STRING "HTML documentation install directory for ${project}")
+
+        # '/.' indicates: copy the contents of the directory directly into
+        # the specified destination, without recreating the last component
+        # of ${SPHINX_BUILD_DIR} implicitly.
+        install(DIRECTORY "${SPHINX_BUILD_DIR}/."
+                DESTINATION "${${project_upper}_INSTALL_SPHINX_HTML_DIR}")
       else()
         message(WARNING Installation of ${builder} not supported)
       endif()
Index: llvm/trunk/docs/CMake.rst
===================================================================
--- llvm/trunk/docs/CMake.rst
+++ llvm/trunk/docs/CMake.rst
@@ -456,6 +456,11 @@
   If enabled then sphinx documentation warnings will be treated as
   errors. Defaults to ON.
 
+**LLVM_INSTALL_SPHINX_HTML_DIR**:STRING
+  The path to install Sphinx-generated HTML documentation to. This path can
+  either be absolute or relative to the CMAKE_INSTALL_PREFIX. Defaults to
+  `share/doc/llvm/html`.
+
 **LLVM_CREATE_XCODE_TOOLCHAIN**:BOOL
   OS X Only: If enabled CMake will generate a target named
   'install-xcode-toolchain'. This target will create a directory at