[PATCH, doc] Document -fsanitize=return

[Marek Polacek]

This patch on top of this patch by Tobias:
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg03082.html
adds the documentation for -fsanitize=return.

Ok for trunk?

2013-12-02  Marek Polacek  <polacek@redhat.com>

	* doc/invoke.texi:

--- gcc/doc/invoke.texi.mp3	2013-12-02 13:34:44.223747841 +0100
+++ gcc/doc/invoke.texi	2013-12-02 13:40:28.658028051 +0100
@@ -5352,6 +5352,14 @@ built with this option turned on will is
 tries to dereference a NULL pointer, or if a reference (possibly an
 rvalue reference) is bound to a NULL pointer.
 
+@item -fsanitize=return
+@opindex fsanitize=return
+
+This option enables the return statement checking.  The application
+built with this option turned on will issue an error message when
+the end of a value-returning function without returning a value is
+reached.  This option works in C++ only.
+
 @end table
 
 While @option{-ftrapv} causes traps for signed overflows to be emitted,

	Marek