Add documentation for "mode" attribute for types.

	* doc/extend.texi (Common Variable Attributes): Move "mode" into
	alphabetical order.
	(Common Type Attributes): Add "mode" attribute.

From-SVN: r262561

gcc/ChangeLog

+2018-07-11  Paul Koning  <ni1d@arrl.net>
+
+	* doc/extend.texi (Common Variable Attributes): Move "mode" into
+	alphabetical order.
+	(Common Type Attributes): Add "mode" attribute.
+
 2018-07-11  Jan Hubicka  <hubicka@ucw.cz>
 
 	* lto-streamer-out.c (DFS::DFS_write_tree_body): Do not

gcc/doc/extend.texi

@@ -6123,6 +6123,19 @@ types (@pxref{Common Function Attributes},
 The message attached to the attribute is affected by the setting of
 the @option{-fmessage-length} option.
 
+@item mode (@var{mode})
+@cindex @code{mode} variable attribute
+This attribute specifies the data type for the declaration---whichever
+type corresponds to the mode @var{mode}.  This in effect lets you
+request an integer or floating-point type according to its width.
+
+@xref{Machine Modes,,, gccint, GNU Compiler Collection (GCC) Internals},
+for a list of the possible keywords for @var{mode}.
+You may also specify a mode of @code{byte} or @code{__byte__} to
+indicate the mode corresponding to a one-byte integer, @code{word} or
+@code{__word__} for the mode of a one-word integer, and @code{pointer}
+or @code{__pointer__} for the mode used to represent pointers.
+
 @item nonstring
 @cindex @code{nonstring} variable attribute
 The @code{nonstring} variable attribute specifies that an object or member
@@ -6158,19 +6171,6 @@ int f (struct Data *pd, const char *s)
 @}
 @end smallexample
 
-@item mode (@var{mode})
-@cindex @code{mode} variable attribute
-This attribute specifies the data type for the declaration---whichever
-type corresponds to the mode @var{mode}.  This in effect lets you
-request an integer or floating-point type according to its width.
-
-@xref{Machine Modes,,, gccint, GNU Compiler Collection (GCC) Internals},
-for a list of the possible keywords for @var{mode}.
-You may also specify a mode of @code{byte} or @code{__byte__} to
-indicate the mode corresponding to a one-byte integer, @code{word} or
-@code{__word__} for the mode of a one-word integer, and @code{pointer}
-or @code{__pointer__} for the mode used to represent pointers.
-
 @item packed
 @cindex @code{packed} variable attribute
 The @code{packed} attribute specifies that a variable or structure field
@@ -7112,6 +7112,19 @@ declaration, the above program would abort when compiled with
 @option{-fstrict-aliasing}, which is on by default at @option{-O2} or
 above.
 
+@item mode (@var{mode})
+@cindex @code{mode} type attribute
+This attribute specifies the data type for the declaration---whichever
+type corresponds to the mode @var{mode}.  This in effect lets you
+request an integer or floating-point type according to its width.
+
+@xref{Machine Modes,,, gccint, GNU Compiler Collection (GCC) Internals},
+for a list of the possible keywords for @var{mode}.
+You may also specify a mode of @code{byte} or @code{__byte__} to
+indicate the mode corresponding to a one-byte integer, @code{word} or
+@code{__word__} for the mode of a one-word integer, and @code{pointer}
+or @code{__pointer__} for the mode used to represent pointers.
+
 @item packed
 @cindex @code{packed} type attribute
 This attribute, attached to @code{struct} or @code{union} type