Update documentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74191 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvmc/doc/LLVMC-Reference.rst b/tools/llvmc/doc/LLVMC-Reference.rst
index 7befe8f..329f9ea 100644
--- a/tools/llvmc/doc/LLVMC-Reference.rst
+++ b/tools/llvmc/doc/LLVMC-Reference.rst
@@ -92,6 +92,12 @@
 
 * ``-v`` - Enable verbose mode, i.e. print out all executed commands.
 
+* ``--save-temps`` - Write temporary files to the current directory and do not
+  delete them on exit. This option can also take an argument: the
+  ``--save-temps=obj`` switch will write files into the directory specified with
+  the ``-o`` option. The ``--save-temps=cwd`` and ``--save-temps`` switches are
+  both synonyms for the default behaviour.
+
 * ``--check-graph`` - Check the compilation for common errors like mismatched
   output/input language names, multiple default edges and cycles. Because of
   plugins, these checks can't be performed at compile-time. Exit with code zero
@@ -108,9 +114,6 @@
   used to set the output file name. Hidden option, useful for debugging LLVMC
   plugins.
 
-* ``--save-temps`` - Write temporary files to the current directory
-  and do not delete them on exit. Hidden option, useful for debugging.
-
 * ``--help``, ``--help-hidden``, ``--version`` - These options have
   their standard meaning.