sourcebuild.texi (target attributes): Document new "inf" effective target keyword.

	* doc/sourcebuild.texi (target attributes): Document new "inf"
	effective target keyword.

From-SVN: r265815

gcc/ChangeLog

+2018-11-05  Paul Koning  <ni1d@arrl.net>
+
+	* doc/sourcebuild.texi (target attributes): Document new "inf"
+	effective target keyword.
+
 2018-11-05  Robin Dapp  <rdapp@linux.ibm.com>
 
 	* config/s390/s390.c (s390_register_move_cost): Increase costs for

gcc/doc/sourcebuild.texi

@@ -1393,8 +1393,11 @@ for any options added with @code{dg-add-options}.
 Target has runtime support for any options added with
 @code{dg-add-options} for any @code{_Float@var{n}} or
 @code{_Float@var{n}x} type.
-@end table
 
+@item inf
+Target supports floating point infinite (@code{inf}) for type
+@code{double}.
+@end table
 @subsubsection Fortran-specific attributes
 
 @table @code